Package vulnerability, severity high

pyasn1 has quadratic CPU use in schemaless BER/CER/DER container decoding

Published October 30, 2026, updated October 31, 2026

pyasn1 has quadratic CPU use in schemaless BER/CER/DER container decoding. Source: GHSA-fm9c-5rcf-2q5p (CVE-2026-119194).

What's affected

• pyasn1 (pypi)>=0.3.3 <0.6.5

What to do

1. Upgrade pyasn1 to 0.6.5 or later.

Check whether you were affected

Pharon tells teams automatically when this affects something they run. To check a machine, run this in Claude Code with the Pharon plugin, in the repository that uses it:

/pharon:check-incident ghsa-fm9c-5rcf-2q5p

References

• https://osv.dev/vulnerability/GHSA-fm9c-5rcf-2q5p
• https://github.com/pyasn1/pyasn1/security/advisories/GHSA-fm9c-5rcf-2q5p
• https://nvd.nist.gov/vuln/detail/CVE-2026-119194
• https://github.com/pyasn1/pyasn1/pull/132
• https://github.com/pyasn1/pyasn1/commit/a36e3a3d067148d26197a6b7221fd0e2cde9cc86
• https://github.com/pyasn1/pyasn1
• https://github.com/pyasn1/pyasn1/releases/tag/v0.6.5

Notice ghsa-fm9c-5rcf-2q5p, signed with key feed-prod-2026-10 (Ed25519). The Pharon CLI verifies the signature before using a notice.