{"id":"CVE-2026-119197","state":"PUBLISHED","title":"pyasn1: Quadratic-complexity denial of service in binary REAL decoding","description":"pyasn1 is a generic ASN.1 library for Python. Prior to 0.6.5, binary REAL decoding builds a large mantissa one octet at a time by shifting a growing integer and slicing the remaining byte string. Attacker-controlled ASN.1 includes a binary-encoded REAL with a large mantissa and reaches BER, CER, or DER decode(), with or without a schema containing REAL. RealPayloadDecoder.valueDecoder repeatedly performs a left shift, OR, and suffix copy for every mantissa octet, making decode time quadratic in mantissa length. A comparatively small REAL value can hold a decoding worker on one CPU core for seconds or longer and cause availability loss. This issue is fixed in version 0.6.5.","publishedAt":"2026-10-29T19:48:52.470Z","updatedAt":"2026-10-30T16:08:50.120Z","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":["pyasn1 pyasn1"],"affected":[{"vendor":"pyasn1","product":"pyasn1","versions":[{"version":"< 0.6.5","status":"affected"}]}],"references":["https://github.com/pyasn1/pyasn1/security/advisories/GHSA-mm57-4v3p-rchx","https://github.com/pyasn1/pyasn1/pull/132","https://github.com/pyasn1/pyasn1/commit/ce3ec3390784780a530047e0e77be5ff457636a4","https://github.com/pyasn1/pyasn1/releases/tag/v0.6.5"],"weaknesses":["CWE-407"],"ingestedAt":"2026-10-30T16:24:06.740Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/119xxx/CVE-2026-119197.json","commit":"52408409ce2a766d916f7a10c578d10655ec3113","baselineCommit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-119197","state":"PUBLISHED","datePublished":"2026-10-29T19:48:52.470Z","dateUpdated":"2026-10-30T16:08:50.120Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-10-29T16:04:48.728Z"},"containers":{"cna":{"title":"pyasn1: Quadratic-complexity denial of service in binary REAL decoding","descriptions":[{"lang":"en","value":"pyasn1 is a generic ASN.1 library for Python. Prior to 0.6.5, binary REAL decoding builds a large mantissa one octet at a time by shifting a growing integer and slicing the remaining byte string. Attacker-controlled ASN.1 includes a binary-encoded REAL with a large mantissa and reaches BER, CER, or DER decode(), with or without a schema containing REAL. RealPayloadDecoder.valueDecoder repeatedly performs a left shift, OR, and suffix copy for every mantissa octet, making decode time quadratic in mantissa length. A comparatively small REAL value can hold a decoding worker on one CPU core for seconds or longer and cause availability loss. This issue is fixed in version 0.6.5."}],"affected":[{"vendor":"pyasn1","product":"pyasn1","versions":[{"version":"< 0.6.5","status":"affected"}]}],"references":[{"url":"https://github.com/pyasn1/pyasn1/security/advisories/GHSA-mm57-4v3p-rchx","name":"https://github.com/pyasn1/pyasn1/security/advisories/GHSA-mm57-4v3p-rchx","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/pyasn1/pyasn1/pull/132","name":"https://github.com/pyasn1/pyasn1/pull/132","tags":["x_refsource_MISC"]},{"url":"https://github.com/pyasn1/pyasn1/commit/ce3ec3390784780a530047e0e77be5ff457636a4","name":"https://github.com/pyasn1/pyasn1/commit/ce3ec3390784780a530047e0e77be5ff457636a4","tags":["x_refsource_MISC"]},{"url":"https://github.com/pyasn1/pyasn1/releases/tag/v0.6.5","name":"https://github.com/pyasn1/pyasn1/releases/tag/v0.6.5","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-407","lang":"en","description":"CWE-407: Inefficient Algorithmic Complexity","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-10-29T19:48:52.470Z"},"source":{"advisory":"GHSA-mm57-4v3p-rchx","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-10-30T15:47:11.257992Z","id":"CVE-2026-119197","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":"2026-10-30T16:08:50.120Z"}}]}}}