========================================================================== Ubuntu Security Notice USN-8134-1 March 30, 2026
pyasn1 vulnerabilities
==========================================================================
A security issue affects these releases of Ubuntu and its derivatives:
- Ubuntu 20.04 LTS
- Ubuntu 18.04 LTS
- Ubuntu 16.04 LTS
- Ubuntu 14.04 LTS
Summary:
Several security issues were fixed in pyasn1.
Software Description:
- pyasn1: ASN.1 library for Python
Details:
It was discovered that pyasn1 could exhaust system resources when
attempting to decode a malformed certificate. An attacker could
possibly use this to cause a denial of service. (CVE-2026-23490)
Kevin Tu discovered that pyasn1 could exhaust system resources via
uncontrolled recursion when attempting to decode malicously-crafted
certificates. An attacker could possibly use this to cause a denial of
service. (CVE-2026-30922)
Update instructions:
The problem can be corrected by updating your system to the following
package versions:
Ubuntu 20.04 LTS
pypy-pyasn1 0.4.2-3ubuntu0.20.04.1~esm1
Available with Ubuntu Pro
python-pyasn1 0.4.2-3ubuntu0.20.04.1~esm1
Available with Ubuntu Pro
python3-pyasn1 0.4.2-3ubuntu0.20.04.1~esm1
Available with Ubuntu Pro
Ubuntu 18.04 LTS
pypy-pyasn1 0.4.2-3ubuntu0.18.04.1~esm1
Available with Ubuntu Pro
python-pyasn1 0.4.2-3ubuntu0.18.04.1~esm1
Available with Ubuntu Pro
python3-pyasn1 0.4.2-3ubuntu0.18.04.1~esm1
Available with Ubuntu Pro
Ubuntu 16.04 LTS
pypy-pyasn1 0.1.9-1ubuntu0.1~esm1
Available with Ubuntu Pro
python-pyasn1 0.1.9-1ubuntu0.1~esm1
Available with Ubuntu Pro
python3-pyasn1 0.1.9-1ubuntu0.1~esm1
Available with Ubuntu Pro
Ubuntu 14.04 LTS
python-pyasn1 0.1.7-1ubuntu2.1+esm1
Available with Ubuntu Pro
python3-pyasn1 0.1.7-1ubuntu2.1+esm1
Available with Ubuntu Pro
In general, a standard system update will make all the necessary changes.
References:
https://ubuntu.com/security/notices/USN-8134-1
CVE-2026-23490, CVE-2026-30922
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