{"id":"CVE-2026-119197","published":"2026-10-29T20:17:30.907","lastModified":"2026-10-29T20:17:30.907","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.","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/ce3ec3390784780a530047e0e77be5ff457636a4","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-mm57-4v3p-rchx","tags":[]}],"exploitRefs":[{"url":"https://github.com/pyasn1/pyasn1/commit/ce3ec3390784780a530047e0e77be5ff457636a4","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-mm57-4v3p-rchx","tags":[]}],"hasPoc":true,"ai":null}