What’s Vulnerable › Vulnerabilities

CVE-2026-23490: pyasn1 has a DoS vulnerability in decoder

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.8% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-01-16 · updated 2026-09-09
• Weakness: CWE-770

Description

pyasn1 is a generic ASN.1 library for Python. Prior to 0.6.2, a Denial-of-Service issue has been found that leads to memory exhaustion from malformed RELATIVE-OID with excessive continuation octets. This vulnerability is fixed in 0.6.2.

Affected products

• Debian Linux: 11.0
• pyasn1: before 0.6.2 — fixed in 0.6.2

How to fix

Upgrade to a fixed version: pyasn1 0.6.2. Check the vendor advisory for mitigations.

References

• https://github.com/pyasn1/pyasn1/commit/3908f144229eed4df24bd569d16e5991ace44970
• https://github.com/pyasn1/pyasn1/releases/tag/v0.6.2
• https://github.com/pyasn1/pyasn1/security/advisories/GHSA-63vm-454h-vhhq
• https://lists.debian.org/debian-lts-announce/2026/02/msg00002.html
• https://access.redhat.com/errata/RHSA-2026:13508
• https://access.redhat.com/errata/RHSA-2026:13512
• https://access.redhat.com/errata/RHSA-2026:13545
• https://access.redhat.com/errata/RHSA-2026:13553
• https://access.redhat.com/errata/RHSA-2026:14020
• https://access.redhat.com/errata/RHSA-2026:17446
• https://access.redhat.com/errata/RHSA-2026:17595
• https://access.redhat.com/errata/RHSA-2026:17611

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