CVE-2026-119197

NameCVE-2026-119197
Descriptionpyasn1 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.
SourceCVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
pyasn1 (PTS)bookworm0.4.8-3+deb12u2vulnerable
bookworm (security)0.4.8-3+deb12u3vulnerable
trixie0.6.1-1+deb13u3vulnerable
trixie (security)0.6.1-1+deb13u2vulnerable
forky, sid0.6.4-1vulnerable

The information below is based on the following data on fixed versions.

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
pyasn1source(unstable)(unfixed)

Notes

https://github.com/pyasn1/pyasn1/security/advisories/GHSA-mm57-4v3p-rchx
Fixed by: https://github.com/pyasn1/pyasn1/commit/ce3ec3390784780a530047e0e77be5ff457636a4 (v0.6.5)

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