{"id":"CVE-2026-119195","published":"2026-10-29T20:17:30.633","lastModified":"2026-10-29T21:17:18.553","description":"pyasn1 is a generic ASN.1 library for Python. Prior to 0.6.5, constructed string and indefinite-length ANY decoding repeatedly concatenates each fragment onto a growing bytes value. Attacker-controlled BER or CER data can use many constructed OCTET STRING or character-string fragments. DER rejects constructed OCTET STRING without a schema, but accepts its definite-length form when asn1Spec selects univ.OctetString; it also accepts constructed character strings such as UTF8String without a schema, even though those encodings are not valid DER. The separate indefinite-length ANY path is reachable in BER and CER when asn1Spec selects univ.Any; DER rejects indefinite lengths. OctetStringPayloadDecoder uses growing header concatenation and AnyPayloadDecoder.indefLenValueDecoder uses growing chunk concatenation, repeatedly copying an increasing prefix and causing quadratic work. A sufficiently fragmented value can occupy decoding workers and cause CPU exhaustion without confidentiality or integrity impact. This issue is fixed in version 0.6.5.","cvssScore":7.5,"cvssSeverity":"HIGH","cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","cwes":["CWE-407"],"vendors":[],"products":[],"references":[{"url":"https://github.com/pyasn1/pyasn1/commit/4ce00797c594b59c1fd6b86d9ebc3ba87b7ec9f9","tags":[]},{"url":"https://github.com/pyasn1/pyasn1/pull/132","tags":[]},{"url":"https://github.com/pyasn1/pyasn1/releases/tag/v0.6.5","tags":[]},{"url":"https://github.com/pyasn1/pyasn1/security/advisories/GHSA-9m75-vc3g-4x39","tags":[]},{"url":"https://github.com/pyasn1/pyasn1/security/advisories/GHSA-9m75-vc3g-4x39","tags":[]}],"exploitRefs":[{"url":"https://github.com/pyasn1/pyasn1/commit/4ce00797c594b59c1fd6b86d9ebc3ba87b7ec9f9","tags":[]},{"url":"https://github.com/pyasn1/pyasn1/pull/132","tags":[]},{"url":"https://github.com/pyasn1/pyasn1/releases/tag/v0.6.5","tags":[]},{"url":"https://github.com/pyasn1/pyasn1/security/advisories/GHSA-9m75-vc3g-4x39","tags":[]},{"url":"https://github.com/pyasn1/pyasn1/security/advisories/GHSA-9m75-vc3g-4x39","tags":[]}],"hasPoc":true,"ai":null}