CVE-2026-34580 Botan has a certificate authentication bypass due to trust anchor confusion
Attackers can bypass certificate authentication by presenting an end-entity certificate with a matching DN to a trusted root, leading to unauthorized access.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-34580?
CVE-2026-34580 is a critical authentication bypass vulnerability in randombit botan, published on 7 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Botan is a C++ cryptography library. In 3.11.0, the function Certificate_Store::certificate_known had a misleading name; it would return true if any certificate in the store had a DN (and subject key identifier, if set) matching that of the argument. It did not check that the cert it found and the cert it was passed were actually the same certificate. In 3.11.0 an extension of path validation logic was made which assumed that certificate_known only returned true if the certificates were in fact identical. The impact is that if an end entity certificate is presented, and its DN (and subject key identifier, if set) match that of any trusted root, the end entity certificate is accepted immediately as if it itself were a trusted root. , This vulnerability is fixed in 3.11.1.
Weakness: CWE-295
Which versions are affected by CVE-2026-34580?
It affects 1 product.
Products include Botan Project Botan.
How do I fix CVE-2026-34580?
Upgrade to a fixed version.
Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.
Is CVE-2026-34580 being exploited?
There is no known exploitation of CVE-2026-34580 in the wild and no public exploit code.
Other vulnerabilities in randombit botan
Sources
Also known as ALPINE-CVE-2026-34580, GHSA-v782-6fq4-q827, UBUNTU-CVE-2026-34580.