{"id":"CVE-2025-66506","state":"PUBLISHED","title":"Fulcio allocates excessive memory during token parsing","description":"Fulcio is a free-to-use certificate authority for issuing code signing certificates for an OpenID Connect (OIDC) identity. Prior to 1.8.3, function identity.extractIssuerURL splits (via a call to strings.Split) its argument (which is untrusted data) on periods. As a result, in the face of a malicious request with an (invalid) OIDC identity token in the payload containing many period characters, a call to extractIssuerURL incurs allocations to the tune of O(n) bytes (where n stands for the length of the function's argument), with a constant factor of about 16. This vulnerability is fixed in 1.8.3.","publishedAt":"2025-12-04T22:04:41.637Z","updatedAt":"2025-12-05T15:32:25.591Z","severity":{"score":7.5,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","source":"GitHub_M"},"assigner":"GitHub_M","products":["sigstore fulcio"],"affected":[{"vendor":"sigstore","product":"fulcio","versions":[{"version":"< 1.8.3","status":"affected"}]}],"references":["https://github.com/sigstore/fulcio/security/advisories/GHSA-f83f-xpx7-ffpw","https://github.com/sigstore/fulcio/commit/765a0e57608b9ef390e1eeeea8595b9054c63a5a"],"weaknesses":["CWE-405"],"ingestedAt":"2026-10-29T20:09:56.034Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2025/66xxx/CVE-2025-66506.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2025-66506","state":"PUBLISHED","datePublished":"2025-12-04T22:04:41.637Z","dateUpdated":"2025-12-05T15:32:25.591Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2025-12-03T15:12:22.978Z"},"containers":{"cna":{"title":"Fulcio allocates excessive memory during token parsing","descriptions":[{"lang":"en","value":"Fulcio is a free-to-use certificate authority for issuing code signing certificates for an OpenID Connect (OIDC) identity. Prior to 1.8.3, function identity.extractIssuerURL splits (via a call to strings.Split) its argument (which is untrusted data) on periods. As a result, in the face of a malicious request with an (invalid) OIDC identity token in the payload containing many period characters, a call to extractIssuerURL incurs allocations to the tune of O(n) bytes (where n stands for the length of the function's argument), with a constant factor of about 16. This vulnerability is fixed in 1.8.3."}],"affected":[{"vendor":"sigstore","product":"fulcio","versions":[{"version":"< 1.8.3","status":"affected"}]}],"references":[{"url":"https://github.com/sigstore/fulcio/security/advisories/GHSA-f83f-xpx7-ffpw","name":"https://github.com/sigstore/fulcio/security/advisories/GHSA-f83f-xpx7-ffpw","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/sigstore/fulcio/commit/765a0e57608b9ef390e1eeeea8595b9054c63a5a","name":"https://github.com/sigstore/fulcio/commit/765a0e57608b9ef390e1eeeea8595b9054c63a5a","tags":["x_refsource_MISC"]}],"metrics":[{"cvssV3_1":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"HIGH","baseScore":7.5,"baseSeverity":"HIGH","confidentialityImpact":"NONE","integrityImpact":"NONE","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","version":"3.1"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-405","lang":"en","description":"CWE-405: Asymmetric Resource Consumption (Amplification)","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2025-12-04T22:04:41.637Z"},"source":{"advisory":"GHSA-f83f-xpx7-ffpw","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2025-12-05T15:32:15.086814Z","id":"CVE-2025-66506","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2025-12-05T15:32:25.591Z"}}]}}}