CVE-2026-48057

Name	CVE-2026-48057
Description	Botan is a C++ cryptography library. Prior to 3.13.0, Botan's X.509 Distinguished Name decoder flattens the Attribute-Value Assertions in each Relative Distinguished Name and loses multi-value RDN grouping before DN name-constraint enforcement. An attacker controlling a name-constrained intermediate CA can issue a certificate with a multi-value RDN whose first Common Name matches the permitted constraint and whose second Common Name is attacker-chosen, causing the constraint check to accept the flattened first value. If the certificate contains no subjectAlternativeName extension, the second Common Name can then be accepted as a hostname; Botan does not fall back to Common Name hostname matching when any subjectAlternativeName is present. The exposure is limited to deployments using DN name constraints, which are uncommon outside internal PKIs, and to certificates without a subjectAlternativeName. This issue is fixed in version 3.13.0.
Source	CVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
botan (PTS)	bookworm	2.19.3+dfsg-1+deb12u1	vulnerable
	trixie	2.19.5+dfsg-4	vulnerable
botan3 (PTS)	trixie	3.7.1+dfsg-2	vulnerable
	trixie (security)	3.12.0+dfsg-2~deb13u1	vulnerable
	forky, sid	3.13.0+dfsg-2	fixed

The information below is based on the following data on fixed versions.

Package	Type	Release	Fixed Version	Urgency	Origin	Debian Bugs
botan	source	(unstable)	(unfixed)
botan3	source	(unstable)	3.13.0+dfsg-2

Notes

https://github.com/randombit/botan/security/advisories/GHSA-3mh2-26h4-wrqc
https://github.com/randombit/botan/pull/5618
Fixed by: https://github.com/randombit/botan/commit/a22260c368373a134ff9778b9d8781edb2e1eb99 (3.13.0)