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CVE-2026-6767

Status: AnalyzedMedium (5.3)—

Other issue in the Libraries component in NSS. This vulnerability was fixed in Firefox 150, Firefox ESR 115.35, Firefox ESR 140.10, Thunderbird 150, and Thunderbird 140.10.

CVSS

Exploitation probability (EPSS)

EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).

Affected technologies (2)

Mozilla — FirefoxMozilla — Thunderbird

CWEs

References

Raw JSON (NVD)

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{
  "id": "CVE-2026-6767",
  "cveTags": [],
  "metrics": {
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-6767",
          "role": "CISA Coordinator",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "yes"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "version": "2.0.3",
          "timestamp": "2026-05-27T17:09:39.086549Z"
        }
      }
    ],
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 5.3,
          "attackVector": "NETWORK",
          "baseSeverity": "MEDIUM",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N",
          "integrityImpact": "NONE",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "NONE",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "LOW"
        },
        "impactScore": 1.4,
        "exploitabilityScore": 3.9
      }
    ]
  },
  "affected": [
    {
      "source": "security@mozilla.org",
      "affectedData": [
        {
          "vendor": "Mozilla",
          "product": "Firefox",
          "versions": [
            {
              "status": "unaffected",
              "version": "115.35",
              "versionType": "rpm",
              "lessThanOrEqual": "115.*"
            },
            {
              "status": "unaffected",
              "version": "140.10",
              "versionType": "rpm",
              "lessThanOrEqual": "140.*"
            },
            {
              "status": "unaffected",
              "version": "150",
              "versionType": "rpm",
              "lessThanOrEqual": "*"
            }
          ]
        },
        {
          "vendor": "Mozilla",
          "product": "Thunderbird",
          "versions": [
            {
              "status": "unaffected",
              "version": "140.10",
              "versionType": "rpm",
              "lessThanOrEqual": "140.*"
            },
            {
              "status": "unaffected",
              "version": "150",
              "versionType": "rpm",
              "lessThanOrEqual": "*"
            }
          ]
        }
      ]
    }
  ],
  "published": "2026-04-21T13:16:22.577",
  "references": [
    {
      "url": "https://bugzilla.mozilla.org/show_bug.cgi?id=2023209",
      "tags": [
        "Permissions Required"
      ],
      "source": "security@mozilla.org"
    },
    {
      "url": "https://www.mozilla.org/security/advisories/mfsa2026-30/",
      "tags": [
        "Vendor Advisory"
      ],
      "source": "security@mozilla.org"
    },
    {
      "url": "https://www.mozilla.org/security/advisories/mfsa2026-31/",
      "tags": [
        "Vendor Advisory"
      ],
      "source": "security@mozilla.org"
    },
    {
      "url": "https://www.mozilla.org/security/advisories/mfsa2026-32/",
      "tags": [
        "Vendor Advisory"
      ],
      "source": "security@mozilla.org"
    },
    {
      "url": "https://www.mozilla.org/security/advisories/mfsa2026-33/",
      "tags": [
        "Vendor Advisory"
      ],
      "source": "security@mozilla.org"
    },
    {
      "url": "https://www.mozilla.org/security/advisories/mfsa2026-34/",
      "tags": [
        "Vendor Advisory"
      ],
      "source": "security@mozilla.org"
    }
  ],
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "type": "Secondary",
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
      "description": [
        {
          "lang": "en",
          "value": "CWE-119"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "Other issue in the Libraries component in NSS. This vulnerability was fixed in Firefox 150, Firefox ESR 115.35, Firefox ESR 140.10, Thunderbird 150, and Thunderbird 140.10."
    }
  ],
  "lastModified": "2026-06-17T11:01:17.820",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:mozilla:firefox:*:*:*:*:esr:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "E69D71F5-CAAA-4F28-AB9F-9F898A52D506",
              "versionEndExcluding": "115.35.0"
            },
            {
              "criteria": "cpe:2.3:a:mozilla:firefox:*:*:*:*:-:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "67B01D49-66FA-4C76-9EB4-2B8CD61FBEB2",
              "versionEndExcluding": "150.0"
            },
            {
              "criteria": "cpe:2.3:a:mozilla:firefox:*:*:*:*:esr:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "528443E0-C15A-4E70-9187-8E1BAAE84A42",
              "versionEndExcluding": "140.10.0",
              "versionStartIncluding": "140.0"
            },
            {
              "criteria": "cpe:2.3:a:mozilla:thunderbird:*:*:*:*:esr:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "6A8A3284-C06C-4591-9548-5324BD91C4FC",
              "versionEndExcluding": "140.10.0",
              "versionStartIncluding": "140.0"
            }
          ],
          "operator": "OR"
        }
      ]
    }
  ],
  "sourceIdentifier": "security@mozilla.org"
}