CVE-2026-59885

Name	CVE-2026-59885
Description	pyasn1 is a generic ASN.1 library for Python. Prior to 0.6.4, the BER, CER, and DER decoders process OBJECT IDENTIFIER and RELATIVE-OID values in quadratic time relative to the number of arcs, so a small crafted payload containing an OID with many arcs consumes excessive CPU per decode() call and can deny service to applications that decode untrusted ASN.1 data. The corresponding encoders have the same quadratic behavior when an application re-encodes previously decoded attacker-supplied values. This issue is fixed in version 0.6.4.
Source	CVE (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 Package	Release	Version	Status
pyasn1 (PTS)	bullseye	0.4.8-1	vulnerable
	bullseye (security)	0.4.8-1+deb11u2	vulnerable
	bookworm, bookworm (security)	0.4.8-3+deb12u2	vulnerable
	trixie (security), trixie	0.6.1-1+deb13u2	vulnerable
	forky, sid	0.6.3-1	vulnerable

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

Package	Type	Release	Fixed Version	Urgency	Origin	Debian Bugs
pyasn1	source	(unstable)	(unfixed)

Notes

https://github.com/pyasn1/pyasn1/security/advisories/GHSA-8ppf-4f7h-5ppj
Fixed by: https://github.com/pyasn1/pyasn1/commit/45bdb19eb7df4b3780fe9c912c63e99bffc39dd9 (v0.6.4)