Improper certificate validation in PkixNameConstraintValidator in Legion of the Bouncy Castle Inc. bc-csharp before 2.7.0 allows an attacker who controls, or can obtain certificates from, a name-constrained intermediate CA to have certificates accepted during PKIX certification path validation for email addresses, DNS names or URI hosts that lie within excluded subtrees applying to that CA, via an rfc822Name, dNSName or uniformResourceIdentifier name whose host ends with a dot, because names and constraints were compared without first removing the RFC 1034 root-label trailing dot, so a fully qualified host name did not match an excluded subtree for the same host written without the dot.
Fix
Patch, vendor advisory and mitigation references on NVD 4
- https://github.com/bcgit/bc-csharp/commit/75c3c576602886180ed92a63c89419e3bd63b392 Patch
- https://github.com/bcgit/bc-csharp/commit/be276e057775a6a674a62e9d9a2583b229978f73 Patch
- https://github.com/bcgit/bc-csharp/commit/f196a22bbf7765cc19b0c4f4645c74ea7ad35e09 Patch
- https://github.com/bcgit/bc-csharp/wiki/CVE-2026-103602 Patch, Vendor Advisory
Every line above is quoted from NVD, CISA, Microsoft, the vendor's own advisory or DISA; nothing is generated.
Change history 1
- First seenCVSS 8.2 · bouncycastleNVD modified 2026-10-28 13:30
Affected (CPE criteria) 1
cpe:2.3:a:bouncycastle:bc-csharp:*:*:*:*:*:*:*:*
References 4
- https://github.com/bcgit/bc-csharp/commit/75c3c576602886180ed92a63c89419e3bd63b392 Patch
- https://github.com/bcgit/bc-csharp/commit/be276e057775a6a674a62e9d9a2583b229978f73 Patch
- https://github.com/bcgit/bc-csharp/commit/f196a22bbf7765cc19b0c4f4645c74ea7ad35e09 Patch
- https://github.com/bcgit/bc-csharp/wiki/CVE-2026-103602 Patch, Vendor Advisory