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Ubuntu 25.10 pyasn1 Critical Denial of Service CVE-2026-23490

ubuntu
Calendar Grey January 22, 2026
Dist Ubuntu Esm H88
Ensure your Ubuntu system is secured by updating pyasn1 to mitigate denial of service vulnerabilities caused by malformed inputs.
pyasn1 could be made to crash if it received specially crafted input.

Summary

pyasn1 could be made to crash if it received specially crafted input.

Software Description:

- pyasn1: ASN.1 library for Python

Details:

It was discovered that pyasn1 incorrectly handled malformed RELATIVE-OIDs

with excessive continuation octets. An attacker could possibly use this

issue to cause pyasn1 to consume memory, leading to a denial of service.

Topics%20covered

Topics Covered

security advisory denial of service critical Ubuntu pyasn1 cve-2026-23490

Update Instructions

The problem can be corrected by updating your system to the following
package versions:

Ubuntu 25.10
  python3-pyasn1                  0.6.1-1ubuntu0.1

Ubuntu 24.04 LTS
  python3-pyasn1                  0.4.8-4ubuntu0.1

Ubuntu 22.04 LTS
  python3-pyasn1                  0.4.8-1ubuntu0.1

In general, a standard system update will make all the necessary changes.

References

https://ubuntu.com/security/notices/USN-7975-1

CVE-2026-23490

Severity
critical
Lowest
Low
Medium
High
Critical

Ubuntu Security Notice USN-7975-1

Topics%20covered

Topics Covered

security advisory denial of service critical Ubuntu pyasn1 cve-2026-23490

Package Information

https://launchpad.net/ubuntu/+source/pyasn1/0.6.1-1ubuntu0.1
https://launchpad.net/ubuntu/+source/pyasn1/0.4.8-4ubuntu0.1
https://launchpad.net/ubuntu/+source/pyasn1/0.4.8-1ubuntu0.1

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