CVE-2025-0239 (GCVE-0-2025-0239)

Vulnerability from cvelistv5 – Published: 2025-01-07 16:07 – Updated: 2026-04-13 14:30
VLAI
Title
Alt-Svc ALPN validation failure when redirected
Summary
When using Alt-Svc, ALPN did not properly validate certificates when the original server is redirecting to an insecure site. This vulnerability was fixed in Firefox 134, Firefox ESR 128.6, Thunderbird 134, and Thunderbird 128.6.
Severity
4 (Medium)
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
CWE
  • CWE-295 - Improper Certificate Validation
Assigner
References
Impacted products
Vendor Product Version
Mozilla Firefox Unaffected: 128.6 , ≤ 128.* (rpm)
Unaffected: 134 , ≤ * (rpm)
Create a notification for this product.
Mozilla Thunderbird Unaffected: 128.6 , ≤ 128.* (rpm)
Unaffected: 134 , ≤ * (rpm)
Create a notification for this product.
Credits
Paul Gerste
Show details on NVD website
To clipboard 

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "cvssV3_1": {
              "attackComplexity": "LOW",
              "attackVector": "LOCAL",
              "availabilityImpact": "NONE",
              "baseScore": 4,
              "baseSeverity": "MEDIUM",
              "confidentialityImpact": "NONE",
              "integrityImpact": "LOW",
              "privilegesRequired": "NONE",
              "scope": "UNCHANGED",
              "userInteraction": "NONE",
              "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N",
              "version": "3.1"
            }
          },
          {
            "other": {
              "content": {
                "id": "CVE-2025-0239",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2025-01-08T16:33:42.534195Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "problemTypes": [
          {
            "descriptions": [
              {
                "cweId": "CWE-295",
                "description": "CWE-295 Improper Certificate Validation",
                "lang": "en",
                "type": "CWE"
              }
            ]
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2025-01-08T16:36:07.964Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      },
      {
        "providerMetadata": {
          "dateUpdated": "2025-11-03T22:33:39.114Z",
          "orgId": "af854a3a-2127-422b-91ae-364da2661108",
          "shortName": "CVE"
        },
        "references": [
          {
            "url": "https://lists.debian.org/debian-lts-announce/2025/01/msg00004.html"
          }
        ],
        "title": "CVE Program Container"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "Firefox",
          "vendor": "Mozilla",
          "versions": [
            {
              "lessThanOrEqual": "128.*",
              "status": "unaffected",
              "version": "128.6",
              "versionType": "rpm"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "134",
              "versionType": "rpm"
            }
          ]
        },
        {
          "product": "Thunderbird",
          "vendor": "Mozilla",
          "versions": [
            {
              "lessThanOrEqual": "128.*",
              "status": "unaffected",
              "version": "128.6",
              "versionType": "rpm"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "134",
              "versionType": "rpm"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "value": "Paul Gerste"
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "supportingMedia": [
            {
              "base64": false,
              "type": "text/html",
              "value": "When using Alt-Svc, ALPN did not properly validate certificates when the original server is redirecting to an insecure site. This vulnerability was fixed in Firefox 134, Firefox ESR 128.6, Thunderbird 134, and Thunderbird 128.6."
            }
          ],
          "value": "When using Alt-Svc, ALPN did not properly validate certificates when the original server is redirecting to an insecure site. This vulnerability was fixed in Firefox 134, Firefox ESR 128.6, Thunderbird 134, and Thunderbird 128.6."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-04-13T14:30:01.233Z",
        "orgId": "f16b083a-5664-49f3-a51e-8d479e5ed7fe",
        "shortName": "mozilla"
      },
      "references": [
        {
          "url": "https://bugzilla.mozilla.org/show_bug.cgi?id=1929156"
        },
        {
          "url": "https://www.mozilla.org/security/advisories/mfsa2025-01/"
        },
        {
          "url": "https://www.mozilla.org/security/advisories/mfsa2025-02/"
        },
        {
          "url": "https://www.mozilla.org/security/advisories/mfsa2025-04/"
        },
        {
          "url": "https://www.mozilla.org/security/advisories/mfsa2025-05/"
        }
      ],
      "title": "Alt-Svc ALPN validation failure when redirected"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "f16b083a-5664-49f3-a51e-8d479e5ed7fe",
    "assignerShortName": "mozilla",
    "cveId": "CVE-2025-0239",
    "datePublished": "2025-01-07T16:07:06.317Z",
    "dateReserved": "2025-01-06T14:49:04.597Z",
    "dateUpdated": "2026-04-13T14:30:01.233Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2025-0239",
      "date": "2026-05-31",
      "epss": "0.0003",
      "percentile": "0.09248"
    },
    "fkie_nvd": {
      "descriptions": "[{\"lang\": \"en\", \"value\": \"When using Alt-Svc, ALPN did not properly validate certificates when the original server is redirecting to an insecure site. This vulnerability affects Firefox \u003c 134, Firefox ESR \u003c 128.6, Thunderbird \u003c 134, and Thunderbird \u003c 128.6.\"}, {\"lang\": \"es\", \"value\": \"Al utilizar Alt-Svc, ALPN no valid\\u00f3 correctamente los certificados cuando el servidor original redireccionaba a un sitio inseguro. Esta vulnerabilidad afecta a Firefox \u0026lt; 134 y Firefox ESR \u0026lt; 128.6.\"}]",
      "id": "CVE-2025-0239",
      "lastModified": "2025-01-13T22:15:15.057",
      "metrics": "{\"cvssMetricV31\": [{\"source\": \"134c704f-9b21-4f2e-91b3-4a467353bcc0\", \"type\": \"Secondary\", \"cvssData\": {\"version\": \"3.1\", \"vectorString\": \"CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N\", \"baseScore\": 4.0, \"baseSeverity\": \"MEDIUM\", \"attackVector\": \"LOCAL\", \"attackComplexity\": \"LOW\", \"privilegesRequired\": \"NONE\", \"userInteraction\": \"NONE\", \"scope\": \"UNCHANGED\", \"confidentialityImpact\": \"NONE\", \"integrityImpact\": \"LOW\", \"availabilityImpact\": \"NONE\"}, \"exploitabilityScore\": 2.5, \"impactScore\": 1.4}]}",
      "published": "2025-01-07T16:15:38.563",
      "references": "[{\"url\": \"https://bugzilla.mozilla.org/show_bug.cgi?id=1929156\", \"source\": \"security@mozilla.org\"}, {\"url\": \"https://www.mozilla.org/security/advisories/mfsa2025-01/\", \"source\": \"security@mozilla.org\"}, {\"url\": \"https://www.mozilla.org/security/advisories/mfsa2025-02/\", \"source\": \"security@mozilla.org\"}, {\"url\": \"https://www.mozilla.org/security/advisories/mfsa2025-04/\", \"source\": \"security@mozilla.org\"}, {\"url\": \"https://www.mozilla.org/security/advisories/mfsa2025-05/\", \"source\": \"security@mozilla.org\"}]",
      "sourceIdentifier": "security@mozilla.org",
      "vulnStatus": "Awaiting Analysis",
      "weaknesses": "[{\"source\": \"134c704f-9b21-4f2e-91b3-4a467353bcc0\", \"type\": \"Secondary\", \"description\": [{\"lang\": \"en\", \"value\": \"CWE-295\"}]}]"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2025-0239\",\"sourceIdentifier\":\"security@mozilla.org\",\"published\":\"2025-01-07T16:15:38.563\",\"lastModified\":\"2026-04-13T15:16:32.543\",\"vulnStatus\":\"Modified\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"When using Alt-Svc, ALPN did not properly validate certificates when the original server is redirecting to an insecure site. This vulnerability was fixed in Firefox 134, Firefox ESR 128.6, Thunderbird 134, and Thunderbird 128.6.\"},{\"lang\":\"es\",\"value\":\"Al utilizar Alt-Svc, ALPN no valid\u00f3 correctamente los certificados cuando el servidor original redireccionaba a un sitio inseguro. Esta vulnerabilidad afecta a Firefox \u0026lt; 134 y Firefox ESR \u0026lt; 128.6.\"}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"134c704f-9b21-4f2e-91b3-4a467353bcc0\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N\",\"baseScore\":4.0,\"baseSeverity\":\"MEDIUM\",\"attackVector\":\"LOCAL\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"NONE\",\"integrityImpact\":\"LOW\",\"availabilityImpact\":\"NONE\"},\"exploitabilityScore\":2.5,\"impactScore\":1.4}]},\"weaknesses\":[{\"source\":\"134c704f-9b21-4f2e-91b3-4a467353bcc0\",\"type\":\"Secondary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-295\"}]}],\"configurations\":[{\"nodes\":[{\"operator\":\"OR\",\"negate\":false,\"cpeMatch\":[{\"vulnerable\":true,\"criteria\":\"cpe:2.3:a:mozilla:firefox:*:*:*:*:esr:*:*:*\",\"versionEndExcluding\":\"128.6.0\",\"matchCriteriaId\":\"AEBB7F43-496D-4A67-8E9E-EEE29913B6DE\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:*\",\"versionEndExcluding\":\"134.0\",\"matchCriteriaId\":\"4FDCA935-A68D-404E-A749-CA3845C709F0\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:*\",\"versionEndExcluding\":\"128.6.0\",\"matchCriteriaId\":\"C92D62DE-A681-4B9D-9640-D12D04392A1B\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:*\",\"versionStartIncluding\":\"129.0\",\"versionEndExcluding\":\"134.0\",\"matchCriteriaId\":\"A633E231-80F8-4A92-BA69-B9BE5BE45D00\"}]}]}],\"references\":[{\"url\":\"https://bugzilla.mozilla.org/show_bug.cgi?id=1929156\",\"source\":\"security@mozilla.org\",\"tags\":[\"Issue Tracking\",\"Permissions Required\"]},{\"url\":\"https://www.mozilla.org/security/advisories/mfsa2025-01/\",\"source\":\"security@mozilla.org\",\"tags\":[\"Vendor Advisory\"]},{\"url\":\"https://www.mozilla.org/security/advisories/mfsa2025-02/\",\"source\":\"security@mozilla.org\",\"tags\":[\"Vendor Advisory\"]},{\"url\":\"https://www.mozilla.org/security/advisories/mfsa2025-04/\",\"source\":\"security@mozilla.org\",\"tags\":[\"Vendor Advisory\"]},{\"url\":\"https://www.mozilla.org/security/advisories/mfsa2025-05/\",\"source\":\"security@mozilla.org\",\"tags\":[\"Vendor Advisory\"]},{\"url\":\"https://lists.debian.org/debian-lts-announce/2025/01/msg00004.html\",\"source\":\"af854a3a-2127-422b-91ae-364da2661108\"}]}}",
    "vulnrichment": {
      "containers": "{\"adp\": [{\"title\": \"CVE Program Container\", \"references\": [{\"url\": \"https://lists.debian.org/debian-lts-announce/2025/01/msg00004.html\"}], \"providerMetadata\": {\"orgId\": \"af854a3a-2127-422b-91ae-364da2661108\", \"shortName\": \"CVE\", \"dateUpdated\": \"2025-11-03T22:33:39.114Z\"}}, {\"title\": \"CISA ADP Vulnrichment\", \"metrics\": [{\"cvssV3_1\": {\"scope\": \"UNCHANGED\", \"version\": \"3.1\", \"baseScore\": 4, \"attackVector\": \"LOCAL\", \"baseSeverity\": \"MEDIUM\", \"vectorString\": \"CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N\", \"integrityImpact\": \"LOW\", \"userInteraction\": \"NONE\", \"attackComplexity\": \"LOW\", \"availabilityImpact\": \"NONE\", \"privilegesRequired\": \"NONE\", \"confidentialityImpact\": \"NONE\"}}, {\"other\": {\"type\": \"ssvc\", \"content\": {\"id\": \"CVE-2025-0239\", \"role\": \"CISA Coordinator\", \"options\": [{\"Exploitation\": \"none\"}, {\"Automatable\": \"no\"}, {\"Technical Impact\": \"partial\"}], \"version\": \"2.0.3\", \"timestamp\": \"2025-01-08T16:33:42.534195Z\"}}}], \"problemTypes\": [{\"descriptions\": [{\"lang\": \"en\", \"type\": \"CWE\", \"cweId\": \"CWE-295\", \"description\": \"CWE-295 Improper Certificate Validation\"}]}], \"providerMetadata\": {\"orgId\": \"134c704f-9b21-4f2e-91b3-4a467353bcc0\", \"shortName\": \"CISA-ADP\", \"dateUpdated\": \"2025-01-08T16:36:02.253Z\"}}], \"cna\": {\"title\": \"Alt-Svc ALPN validation failure when redirected\", \"credits\": [{\"lang\": \"en\", \"value\": \"Paul Gerste\"}], \"affected\": [{\"vendor\": \"Mozilla\", \"product\": \"Firefox\", \"versions\": [{\"status\": \"unaffected\", \"version\": \"128.6\", \"versionType\": \"rpm\", \"lessThanOrEqual\": \"128.*\"}, {\"status\": \"unaffected\", \"version\": \"134\", \"versionType\": \"rpm\", \"lessThanOrEqual\": \"*\"}]}, {\"vendor\": \"Mozilla\", \"product\": \"Thunderbird\", \"versions\": [{\"status\": \"unaffected\", \"version\": \"128.6\", \"versionType\": \"rpm\", \"lessThanOrEqual\": \"128.*\"}, {\"status\": \"unaffected\", \"version\": \"134\", \"versionType\": \"rpm\", \"lessThanOrEqual\": \"*\"}]}], \"references\": [{\"url\": \"https://bugzilla.mozilla.org/show_bug.cgi?id=1929156\"}, {\"url\": \"https://www.mozilla.org/security/advisories/mfsa2025-01/\"}, {\"url\": \"https://www.mozilla.org/security/advisories/mfsa2025-02/\"}, {\"url\": \"https://www.mozilla.org/security/advisories/mfsa2025-04/\"}, {\"url\": \"https://www.mozilla.org/security/advisories/mfsa2025-05/\"}], \"descriptions\": [{\"lang\": \"en\", \"value\": \"When using Alt-Svc, ALPN did not properly validate certificates when the original server is redirecting to an insecure site. This vulnerability was fixed in Firefox 134, Firefox ESR 128.6, Thunderbird 134, and Thunderbird 128.6.\", \"supportingMedia\": [{\"type\": \"text/html\", \"value\": \"When using Alt-Svc, ALPN did not properly validate certificates when the original server is redirecting to an insecure site. This vulnerability was fixed in Firefox 134, Firefox ESR 128.6, Thunderbird 134, and Thunderbird 128.6.\", \"base64\": false}]}], \"providerMetadata\": {\"orgId\": \"f16b083a-5664-49f3-a51e-8d479e5ed7fe\", \"shortName\": \"mozilla\", \"dateUpdated\": \"2026-04-13T14:30:01.233Z\"}}}",
      "cveMetadata": "{\"cveId\": \"CVE-2025-0239\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2026-04-13T14:30:01.233Z\", \"dateReserved\": \"2025-01-06T14:49:04.597Z\", \"assignerOrgId\": \"f16b083a-5664-49f3-a51e-8d479e5ed7fe\", \"datePublished\": \"2025-01-07T16:07:06.317Z\", \"assignerShortName\": \"mozilla\"}",
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}


Log in or create an account to share your comment.




Tags
Taxonomy of the tags.





Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

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.