CVE-2026-119197
highpyasn1 is a generic ASN.1 library for Python.
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.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Affected products
Not reported by the source (unknown — not "none").
Weakness classification (CWE)
Source: NVD / CISA. “NVD-CWE-Other” and “NVD-CWE-noinfo” mean NVD could not assign a specific weakness.
Mitigation & advisories
No vendor advisory or patch reference tagged by NVD. Check the references below.
References
- https://github.com/pyasn1/pyasn1/commit/ce3ec3390784780a530047e0e77be5ff457636a4 security-advisories@github.com
- https://github.com/pyasn1/pyasn1/pull/132 security-advisories@github.com
- https://github.com/pyasn1/pyasn1/releases/tag/v0.6.5 security-advisories@github.com
- https://github.com/pyasn1/pyasn1/security/advisories/GHSA-mm57-4v3p-rchx security-advisories@github.com