Vulnerability-Lookup

UBUNTU-CVE-2026-108981 (CVE-2026-108981)

Vulnerability from osv_ubuntu – Published: 2026-10-13 00:00 – Updated: 2026-10-13 00:00 – Source website

Details

ngx_cache_purge before 3.0.4 can allow file deletion via a symlink attack in certain situations where nginx and a served application (e.g., WordPress) run under the same user account. The attacker must be able to create a symlink inside the cache path. Version 3.0.4 fixes this for the case of a symlink created at an arbitrary earlier time, but does not resolve an applicable TOCTOU race condition. (The ngx_cache_purge module follows symlinks while walking the cache directory tree during purge operations. The module relies on nginx's ngx_walk_tree(), which relies on stat() and therefore follows symlinks.)

Severity

3.6 (Low)


                    
                      CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:L

N/A (UNKNOWN)


                    
                      medium

References

URL

Type

	https://ubuntu.com/security/CVE-2026-108981	REPORT
	https://www.cve.org/CVERecord?id=CVE-2026-108981	REPORT
	https://github.com/nginx-modules/ngx_cache_purge/…	REPORT
	https://github.com/nginx-modules/ngx_cache_purge/…	REPORT
	https://github.com/nginx-modules/ngx_cache_purge/…	REPORT

JSON

To clipboard

{
  "affected": [
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libnginx-mod-http-cache-purge",
            "binary_version": "1:2.3-6build2"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:24.04:LTS",
        "name": "libnginx-mod-http-cache-purge",
        "purl": "pkg:deb/ubuntu/libnginx-mod-http-cache-purge@1:2.3-6build2?arch=source\u0026distro=noble"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1:2.3-5",
        "1:2.3-6",
        "1:2.3-6build2"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libnginx-mod-http-cache-purge",
            "binary_version": "1:2.5.5-1build2"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:26.04:LTS",
        "name": "libnginx-mod-http-cache-purge",
        "purl": "pkg:deb/ubuntu/libnginx-mod-http-cache-purge@1:2.5.5-1build2?arch=source\u0026distro=resolute"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1:2.5.3-3build1",
        "1:2.5.4-1",
        "1:2.5.4-1build1",
        "1:2.5.5-1",
        "1:2.5.5-1build1",
        "1:2.5.5-1build2"
      ]
    }
  ],
  "aliases": [],
  "details": "ngx_cache_purge before 3.0.4 can allow file deletion via a symlink attack in certain situations where nginx and a served application (e.g., WordPress) run under the same user account. The attacker must be able to create a symlink inside the cache path. Version 3.0.4 fixes this for the case of a symlink created at an arbitrary earlier time, but does not resolve an applicable TOCTOU race condition. (The ngx_cache_purge module follows symlinks while walking the cache directory tree during purge operations. The module relies on nginx\u0027s ngx_walk_tree(), which relies on stat() and therefore follows symlinks.)",
  "id": "UBUNTU-CVE-2026-108981",
  "modified": "2026-10-13T00:00:00Z",
  "published": "2026-10-13T00:00:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-108981"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-108981"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/nginx-modules/ngx_cache_purge/commit/a6da1352f52a8a02dd6828e88c39ed42fddcee96"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/nginx-modules/ngx_cache_purge/pull/72"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/nginx-modules/ngx_cache_purge/releases/tag/3.0.4"
    }
  ],
  "related": [],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:L",
      "type": "CVSS_V3"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2026-108981"
  ]
}

CVE-2026-108981 (GCVE-0-2026-108981)

Vulnerability from cvelistv5 – Published: 2026-10-12 02:27 – Updated: 2026-10-14 17:18

Summary

Severity

3.6 (Low)


                        
                          CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:L

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-10-14 17:17 UTC

CWE

CWE-61 - UNIX Symbolic Link (Symlink) Following

Assigner

mitre CNA under the mitre root

CNA scorecard E 28/100 over 2347 records in the last 180 days details

References

3 references

URL	Tags
https://github.com/nginx-modules/ngx_cache_purge/…	patch
https://github.com/nginx-modules/ngx_cache_purge/…	patch
https://github.com/nginx-modules/ngx_cache_purge/…

Impacted products

1 product

Vendor	Product	Version
denji	ngx_cache_purge	Affected: 2.4.0 , ≤ 2.5.6 (semver) Affected: 3.0.0 , < 3.0.4 (semver)

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-108981",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-10-14T17:17:47.968041Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-10-14T17:18:00.208Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "modules": [
            "purge_all",
            "partial/wildcard key purge",
            "asynchronous purge queue",
            "vary-aware variant deletion"
          ],
          "product": "ngx_cache_purge",
          "programFiles": [
            "ngx_cache_purge_module.c"
          ],
          "programRoutines": [
            {
              "name": "ngx_http_cache_purge_all"
            },
            {
              "name": "ngx_http_cache_purge_partial"
            },
            {
              "name": "ngx_http_cache_purge_process_queue"
            },
            {
              "name": "ngx_http_cache_purge_delete_variants"
            }
          ],
          "repo": "https://github.com/nginx-modules/ngx_cache_purge",
          "vendor": "denji",
          "versions": [
            {
              "lessThanOrEqual": "2.5.6",
              "status": "affected",
              "version": "2.4.0",
              "versionType": "semver"
            },
            {
              "lessThan": "3.0.4",
              "status": "affected",
              "version": "3.0.0",
              "versionType": "semver"
            }
          ]
        }
      ],
      "configurations": [
        {
          "lang": "en",
          "supportingMedia": [
            {
              "base64": false,
              "type": "text/html",
              "value": "\u003ccode\u003e\n\nnginx built with the ngx_cache_purge module and a proxy, fastcgi, scgi or uwsgi cache path with purge walks in use (purge_all, a wildcard purge, or cache_purge_vary_aware; arbitrary file deletion requires purge_all or a wildcard purge whose key reduces to an empty prefix), and an attacker able to create a symbolic link inside the cache path, for example when nginx and a web application run as the same user. The attacker does not need PURGE access: any legitimate purge of this kind, such as an automatic purge_all issued by a cache plugin, triggers the traversal.\n\n\u003c/code\u003e\n\n\n\n\u003cbr\u003e"
            }
          ],
          "value": "nginx built with the ngx_cache_purge module and a proxy, fastcgi, scgi or uwsgi cache path with purge walks in use (purge_all, a wildcard purge, or cache_purge_vary_aware; arbitrary file deletion requires purge_all or a wildcard purge whose key reduces to an empty prefix), and an attacker able to create a symbolic link inside the cache path, for example when nginx and a web application run as the same user. The attacker does not need PURGE access: any legitimate purge of this kind, such as an automatic purge_all issued by a cache plugin, triggers the traversal."
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "ngx_cache_purge before 3.0.4 can allow file deletion via a symlink attack in certain situations where nginx and a served application (e.g., WordPress) run under the same user account. The attacker must be able to create a symlink inside the cache path. Version 3.0.4 fixes this for the case of a symlink created at an arbitrary earlier time, but does not resolve an applicable TOCTOU race condition. (The ngx_cache_purge module follows symlinks while walking the cache directory tree during purge operations. The module relies on nginx\u0027s ngx_walk_tree(), which relies on stat() and therefore follows symlinks.)"
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "HIGH",
            "attackVector": "LOCAL",
            "availabilityImpact": "LOW",
            "baseScore": 3.6,
            "baseSeverity": "LOW",
            "confidentialityImpact": "NONE",
            "integrityImpact": "LOW",
            "privilegesRequired": "LOW",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:L",
            "version": "3.1"
          },
          "format": "CVSS",
          "scenarios": [
            {
              "lang": "en",
              "value": "GENERAL"
            }
          ]
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-61",
              "description": "CWE-61 UNIX Symbolic Link (Symlink) Following",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-12T02:27:15.378Z",
        "orgId": "8254265b-2729-46b6-b9e3-3dfca2d5bfca",
        "shortName": "mitre"
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      "references": [
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          "tags": [
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          "url": "https://github.com/nginx-modules/ngx_cache_purge/pull/72"
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          "tags": [
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          "url": "https://github.com/nginx-modules/ngx_cache_purge/commit/a6da1352f52a8a02dd6828e88c39ed42fddcee96"
        },
        {
          "url": "https://github.com/nginx-modules/ngx_cache_purge/releases/tag/3.0.4"
        }
      ],
      "solutions": [
        {
          "lang": "en",
          "supportingMedia": [
            {
              "base64": false,
              "type": "text/html",
              "value": "Fixed in commit a6da135 (PR #72) on the releases/stable-3.0 branch. 2.4 through 2.5.6 users should upgrade to 3.x, or backport the change to the two ngx_walk_tree() call sites in those versions.\n\n\n\n\n\n\u003cbr\u003e"
            }
          ],
          "value": "Fixed in commit a6da135 (PR #72) on the releases/stable-3.0 branch. 2.4 through 2.5.6 users should upgrade to 3.x, or backport the change to the two ngx_walk_tree() call sites in those versions."
        }
      ],
      "workarounds": [
        {
          "lang": "en",
          "supportingMedia": [
            {
              "base64": false,
              "type": "text/html",
              "value": "Restrict write access to the cache directories and all of their parent directories to the nginx user only, and do not run nginx and untrusted application code (for example PHP-FPM) as the same user. Remove any symbolic links found inside configured cache paths (find \u0026lt;cache_path\u0026gt; -type l). These measures also limit the similar traversal in nginx\u0027s own cache loader, which the fix in the module does not change.\n\n\n\n\n\n\u003cbr\u003e"
            }
          ],
          "value": "Restrict write access to the cache directories and all of their parent directories to the nginx user only, and do not run nginx and untrusted application code (for example PHP-FPM) as the same user. Remove any symbolic links found inside configured cache paths (find \u003ccache_path\u003e -type l). These measures also limit the similar traversal in nginx\u0027s own cache loader, which the fix in the module does not change."
        }
      ],
      "x_generator": {
        "engine": "CVE-Request-form 0.0.1"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "8254265b-2729-46b6-b9e3-3dfca2d5bfca",
    "assignerShortName": "mitre",
    "cveId": "CVE-2026-108981",
    "datePublished": "2026-10-12T02:27:15.378Z",
    "dateReserved": "2026-10-12T02:27:14.593Z",
    "dateUpdated": "2026-10-14T17:18:00.208Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

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

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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.
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