Vulnerability-Lookup

CVE-2026-77353 (GCVE-0-2026-77353)

Vulnerability from cvelistv5 – Published: 2026-08-31 21:22 – Updated: 2026-08-31 21:22

Title

Wallos: iCalendar Injection via CRLF in Subscription Name/Notes Export

Summary

Wallos is an open-source, self-hostable personal subscription tracker. Prior to version 5.0.0, Wallos allows authenticated users to inject arbitrary iCalendar properties and events into their exported .ics feed by embedding raw CRLF sequences in subscription names or notes. Because the input validation layer only encodes HTML metacharacters but never strips newlines, and the export layer decodes those entities back before writing iCal output, an attacker with any valid account can craft a subscription whose name breaks out of the current VEVENT block and inserts fully attacker-controlled calendar events — including spoofed organizers, arbitrary email addresses in ATTENDEE properties, and misleading event content — into any calendar application subscribed to that feed. This issue has been patched in version 5.0.0.

Severity

4.6 (Medium)


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

CWE

CWE-74 - Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')
CWE-116 - Improper Encoding or Escaping of Output

Assigner

GitHub_M mitre root

References

3 references

URL	Tags
https://github.com/ellite/Wallos/security/advisor…	x_refsource_CONFIRM
https://github.com/ellite/Wallos/commit/11eaf402e…	x_refsource_MISC
https://github.com/ellite/Wallos/releases/tag/v5.0.0	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version	CPE status
ellite	Wallos	Affected: < 5.0.0	guessed

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "cna": {
      "affected": [
        {
          "product": "Wallos",
          "vendor": "ellite",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 5.0.0"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "Wallos is an open-source, self-hostable personal subscription tracker. Prior to version 5.0.0, Wallos allows authenticated users to inject arbitrary iCalendar properties and events into their exported .ics feed by embedding raw CRLF sequences in subscription names or notes. Because the input validation layer only encodes HTML metacharacters but never strips newlines, and the export layer decodes those entities back before writing iCal output, an attacker with any valid account can craft a subscription whose name breaks out of the current VEVENT block and inserts fully attacker-controlled calendar events \u2014 including spoofed organizers, arbitrary email addresses in ATTENDEE properties, and misleading event content \u2014 into any calendar application subscribed to that feed. This issue has been patched in version 5.0.0."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "NONE",
            "baseScore": 4.6,
            "baseSeverity": "MEDIUM",
            "confidentialityImpact": "LOW",
            "integrityImpact": "LOW",
            "privilegesRequired": "LOW",
            "scope": "UNCHANGED",
            "userInteraction": "REQUIRED",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:N",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-74",
              "description": "CWE-74: Improper Neutralization of Special Elements in Output Used by a Downstream Component (\u0027Injection\u0027)",
              "lang": "en",
              "type": "CWE"
            }
          ]
        },
        {
          "descriptions": [
            {
              "cweId": "CWE-116",
              "description": "CWE-116: Improper Encoding or Escaping of Output",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-31T21:22:35.147Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/ellite/Wallos/security/advisories/GHSA-q2r8-m9wm-5547",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/ellite/Wallos/security/advisories/GHSA-q2r8-m9wm-5547"
        },
        {
          "name": "https://github.com/ellite/Wallos/commit/11eaf402e841a628c68a805694227ce66c45f6f3",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/ellite/Wallos/commit/11eaf402e841a628c68a805694227ce66c45f6f3"
        },
        {
          "name": "https://github.com/ellite/Wallos/releases/tag/v5.0.0",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/ellite/Wallos/releases/tag/v5.0.0"
        }
      ],
      "source": {
        "advisory": "GHSA-q2r8-m9wm-5547",
        "discovery": "UNKNOWN"
      },
      "title": "Wallos: iCalendar Injection via CRLF in Subscription Name/Notes Export"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-77353",
    "datePublished": "2026-08-31T21:22:35.147Z",
    "dateReserved": "2026-08-20T19:28:35.244Z",
    "dateUpdated": "2026-08-31T21:22:35.147Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-77353",
      "date": "2026-09-01",
      "epss": "0.00165",
      "percentile": "0.06043"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-77353\",\"sourceIdentifier\":\"security-advisories@github.com\",\"published\":\"2026-08-31T22:17:20.743\",\"lastModified\":\"2026-08-31T22:17:20.743\",\"vulnStatus\":\"Received\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"Wallos is an open-source, self-hostable personal subscription tracker. Prior to version 5.0.0, Wallos allows authenticated users to inject arbitrary iCalendar properties and events into their exported .ics feed by embedding raw CRLF sequences in subscription names or notes. Because the input validation layer only encodes HTML metacharacters but never strips newlines, and the export layer decodes those entities back before writing iCal output, an attacker with any valid account can craft a subscription whose name breaks out of the current VEVENT block and inserts fully attacker-controlled calendar events \u2014 including spoofed organizers, arbitrary email addresses in ATTENDEE properties, and misleading event content \u2014 into any calendar application subscribed to that feed. This issue has been patched in version 5.0.0.\"}],\"affected\":[{\"source\":\"security-advisories@github.com\",\"affectedData\":[{\"vendor\":\"ellite\",\"product\":\"Wallos\",\"versions\":[{\"version\":\"\u003c 5.0.0\",\"status\":\"affected\"}]}]}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"security-advisories@github.com\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:N\",\"baseScore\":4.6,\"baseSeverity\":\"MEDIUM\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"LOW\",\"userInteraction\":\"REQUIRED\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"LOW\",\"integrityImpact\":\"LOW\",\"availabilityImpact\":\"NONE\"},\"exploitabilityScore\":2.1,\"impactScore\":2.5}]},\"weaknesses\":[{\"source\":\"security-advisories@github.com\",\"type\":\"Primary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-74\"},{\"lang\":\"en\",\"value\":\"CWE-116\"}]}],\"references\":[{\"url\":\"https://github.com/ellite/Wallos/commit/11eaf402e841a628c68a805694227ce66c45f6f3\",\"source\":\"security-advisories@github.com\"},{\"url\":\"https://github.com/ellite/Wallos/releases/tag/v5.0.0\",\"source\":\"security-advisories@github.com\"},{\"url\":\"https://github.com/ellite/Wallos/security/advisories/GHSA-q2r8-m9wm-5547\",\"source\":\"security-advisories@github.com\"}]}}"
  }
}

FKIE_CVE-2026-77353

Vulnerability from fkie_nvd - Published: 2026-08-31 22:17 - Updated: 2026-08-31 22:17

Severity

4.6 (Medium) - CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:N

Summary

References

	URL	Tags
	security-advisories@github.com	https://github.com/ellite/Wallos/commit/11eaf402e841a628c68a805694227ce66c45f6f3
	security-advisories@github.com	https://github.com/ellite/Wallos/releases/tag/v5.0.0
	security-advisories@github.com	https://github.com/ellite/Wallos/security/advisories/GHSA-q2r8-m9wm-5547

Impacted products

	Vendor	Product	Version

JSON

To clipboard

{
  "affected": [
    {
      "affectedData": [
        {
          "product": "Wallos",
          "vendor": "ellite",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 5.0.0"
            }
          ]
        }
      ],
      "source": "security-advisories@github.com"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "Wallos is an open-source, self-hostable personal subscription tracker. Prior to version 5.0.0, Wallos allows authenticated users to inject arbitrary iCalendar properties and events into their exported .ics feed by embedding raw CRLF sequences in subscription names or notes. Because the input validation layer only encodes HTML metacharacters but never strips newlines, and the export layer decodes those entities back before writing iCal output, an attacker with any valid account can craft a subscription whose name breaks out of the current VEVENT block and inserts fully attacker-controlled calendar events \u2014 including spoofed organizers, arbitrary email addresses in ATTENDEE properties, and misleading event content \u2014 into any calendar application subscribed to that feed. This issue has been patched in version 5.0.0."
    }
  ],
  "id": "CVE-2026-77353",
  "lastModified": "2026-08-31T22:17:20.743",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "NONE",
          "baseScore": 4.6,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "LOW",
          "integrityImpact": "LOW",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "REQUIRED",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:N",
          "version": "3.1"
        },
        "exploitabilityScore": 2.1,
        "impactScore": 2.5,
        "source": "security-advisories@github.com",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-08-31T22:17:20.743",
  "references": [
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/ellite/Wallos/commit/11eaf402e841a628c68a805694227ce66c45f6f3"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/ellite/Wallos/releases/tag/v5.0.0"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/ellite/Wallos/security/advisories/GHSA-q2r8-m9wm-5547"
    }
  ],
  "sourceIdentifier": "security-advisories@github.com",
  "vulnStatus": "Received",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-74"
        },
        {
          "lang": "en",
          "value": "CWE-116"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Primary"
    }
  ]
}

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.

Detection rules are retrieved from Rulezet.

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.

Action not permitted

CVE-2026-77353 (GCVE-0-2026-77353)

FKIE_CVE-2026-77353

Tags

Sightings

Nomenclature