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Fedora 43 Releases pyOpenSSL Critical Buffer Overflow Patch Update

Linuxsecurity •LinuxSecurity Advisories • March 27, 2026

Wycheproof test vectors. Update Information : Update pyOpenSSL to v26.0.0 (security update) Update python-cryptography to v46.0.5 (dependency of pyOpenSSL 26) Update rust-asn1 to 0.22 (dependency of python-cryptography) Update kryoptic to v1.5 (required for rust-asn1 bump to 0.22) The security status of this update is only for pyOpenSSL.

Wycheproof test vectors.

Update pyOpenSSL to v26.0.0 (security update) Update python-cryptography to v46.0.5 (dependency of pyOpenSSL 26) Update rust-asn1 to 0.22 (dependency of python-cryptography) Update kryoptic to v1.5 (required for rust-asn1 bump to 0.22) The security status of this update is only for pyOpenSSL.

* Mon Jan 26 2026 Jakub Jelen - 0.6.0-1 - First Fedora release (#2432331)

[ 1 ] Bug #2433650 - python-cryptography-46.0.5 is available [ 2 ] Bug #2447727 - pyOpenSSL-26.0.0 is available [ 3 ] Bug #2448652 - CVE-2026-27459 pyOpenSSL: DTLS cookie callback buffer overflow [fedora-all]

This update can be installed with the "dnf" update program. Use su -c 'dnf upgrade --advisory FEDORA-2026-9d5b9f45ec' at the command line. For more information, refer to the dnf documentation available at

The full story

This article is one source in a clustered incident — the cluster page carries the summary, timeline and every other outlet covering it.

Critical Buffer Overflow Vulnerability in pyOpenSSL Requires Immediate Action A critical buffer overflow vulnerability (CVE-2026-27459) in pyOpenSSL was published on March 17, 2026. This vulnerability affects systems using pyOpenSSL and is linked to a DTLS cookie callback buffer overflow. The updates released include pyOpenSSL version 26.0.0 and python-cryptography version 46.0.5, which are essential for mitigating this threat. The updates also involve dependencies like rust-asn1 and kryoptic. Users are advised to upgrade their systems using the 'dnf' update program to ensure protection against potential exploits. The security status of this update is particularly focused on the pyOpenSSL package. Failure to apply these updates may leave systems vulnerable to attacks that exploit this buffer overflow. The updates are available for immediate installation. 3 sources 76

Extracted Entities

Companies (1)

Fedora

CVEs (1)

CVE-2026-27459