Vulnerability-Lookup

GHSA-R27J-R277-J56H

Vulnerability from github – Published: 2026-01-28 09:30 – Updated: 2026-01-28 18:30

Details

CSS-based exfiltration of the content from partially encrypted emails when allowing remote content. This vulnerability affects Thunderbird < 147.0.1 and Thunderbird < 140.7.1.

Severity ?

4.3 (Medium)


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

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{
  "affected": [],
  "aliases": [
    "CVE-2026-0818"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-116"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-01-28T08:16:03Z",
    "severity": "MODERATE"
  },
  "details": "CSS-based exfiltration of the content from partially encrypted emails when allowing remote content. This vulnerability affects Thunderbird \u003c 147.0.1 and Thunderbird \u003c 140.7.1.",
  "id": "GHSA-r27j-r277-j56h",
  "modified": "2026-01-28T18:30:47Z",
  "published": "2026-01-28T09:30:31Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-0818"
    },
    {
      "type": "WEB",
      "url": "https://bugzilla.mozilla.org/show_bug.cgi?id=1881530"
    },
    {
      "type": "WEB",
      "url": "https://www.mozilla.org/security/advisories/mfsa2026-07"
    },
    {
      "type": "WEB",
      "url": "https://www.mozilla.org/security/advisories/mfsa2026-08"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2026-0818 (GCVE-0-2026-0818)

Vulnerability from cvelistv5 – Published: 2026-01-28 07:39 – Updated: 2026-01-28 16:51

Title

CSS-based exfiltration of the content from partially encrypted emails when allowing remote content

Summary

CSS-based exfiltration of the content from partially encrypted emails when allowing remote content. This vulnerability affects Thunderbird < 147.0.1 and Thunderbird < 140.7.1.

Severity ?

4.3 (Medium)


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

CWE

CWE-200 - Exposure of Sensitive Information to an Unauthorized Actor
CWE-352 - Cross-Site Request Forgery (CSRF)
CWE-116 - Improper Encoding or Escaping of Output

Assigner

mozilla

References

URL

Tags

	https://bugzilla.mozilla.org/show_bug.cgi?id=1881530
	https://www.mozilla.org/security/advisories/mfsa2…
	https://www.mozilla.org/security/advisories/mfsa2…

Impacted products

Vendor

Product

Version

Mozilla

Thunderbird

Affected: unspecified , < 147.0.1 (custom)

Mozilla

Thunderbird

Affected: unspecified , < 140.7.1 (custom)

Credits

Leon Trampert, Daniel Weber, Christian Rossow, Michael Schwarz

Show details on NVD website

JSON

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{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "cvssV3_1": {
              "attackComplexity": "LOW",
              "attackVector": "NETWORK",
              "availabilityImpact": "NONE",
              "baseScore": 4.3,
              "baseSeverity": "MEDIUM",
              "confidentialityImpact": "LOW",
              "integrityImpact": "NONE",
              "privilegesRequired": "NONE",
              "scope": "UNCHANGED",
              "userInteraction": "REQUIRED",
              "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N",
              "version": "3.1"
            }
          },
          {
            "other": {
              "content": {
                "id": "CVE-2026-0818",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-01-28T16:50:27.156500Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "problemTypes": [
          {
            "descriptions": [
              {
                "cweId": "CWE-200",
                "description": "CWE-200 Exposure of Sensitive Information to an Unauthorized Actor",
                "lang": "en",
                "type": "CWE"
              }
            ]
          },
          {
            "descriptions": [
              {
                "cweId": "CWE-352",
                "description": "CWE-352 Cross-Site Request Forgery (CSRF)",
                "lang": "en",
                "type": "CWE"
              }
            ]
          },
          {
            "descriptions": [
              {
                "cweId": "CWE-116",
                "description": "CWE-116 Improper Encoding or Escaping of Output",
                "lang": "en",
                "type": "CWE"
              }
            ]
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-01-28T16:51:16.955Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "Thunderbird",
          "vendor": "Mozilla",
          "versions": [
            {
              "lessThan": "147.0.1",
              "status": "affected",
              "version": "unspecified",
              "versionType": "custom"
            }
          ]
        },
        {
          "product": "Thunderbird",
          "vendor": "Mozilla",
          "versions": [
            {
              "lessThan": "140.7.1",
              "status": "affected",
              "version": "unspecified",
              "versionType": "custom"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "value": "Leon Trampert, Daniel Weber, Christian Rossow, Michael Schwarz"
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "supportingMedia": [
            {
              "base64": false,
              "type": "text/html",
              "value": "CSS-based exfiltration of the content from partially encrypted emails when allowing remote content. This vulnerability affects Thunderbird \u003c 147.0.1 and Thunderbird \u003c 140.7.1."
            }
          ],
          "value": "CSS-based exfiltration of the content from partially encrypted emails when allowing remote content. This vulnerability affects Thunderbird \u003c 147.0.1 and Thunderbird \u003c 140.7.1."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-01-28T07:39:17.467Z",
        "orgId": "f16b083a-5664-49f3-a51e-8d479e5ed7fe",
        "shortName": "mozilla"
      },
      "references": [
        {
          "url": "https://bugzilla.mozilla.org/show_bug.cgi?id=1881530"
        },
        {
          "url": "https://www.mozilla.org/security/advisories/mfsa2026-07/"
        },
        {
          "url": "https://www.mozilla.org/security/advisories/mfsa2026-08/"
        }
      ],
      "title": "CSS-based exfiltration of the content from partially encrypted emails when allowing remote content"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "f16b083a-5664-49f3-a51e-8d479e5ed7fe",
    "assignerShortName": "mozilla",
    "cveId": "CVE-2026-0818",
    "datePublished": "2026-01-28T07:39:17.467Z",
    "dateReserved": "2026-01-09T16:32:39.712Z",
    "dateUpdated": "2026-01-28T16:51:16.955Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date

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.

Action not permitted

GHSA-R27J-R277-J56H

CVE-2026-0818 (GCVE-0-2026-0818)

Tags

Sightings

Nomenclature