CVE-2026-103602Name constraints bypass via trailing dot in rfc822Name, dNSName and URI hosts
Updated under an hour ago ()
Does this affect you?
It affects Legion of the Bouncy Castle Inc. bc-csharp. Add what you run to find out whether that includes you.
EPSS puts the chance of exploitation in the next 30 days at 0.24%, higher than 14% of scored CVEs.
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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.
- CVSS
- 8.2 HIGH (v4.0, CNA)CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N
- Weakness (CWE)
- CWE-295
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- 0.24% (percentile 14)
- Assigned by
- bcorg
- NVD analysis
- Undergoing Analysis
- Record last updated
- Oct 2, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
Legion of the Bouncy Castle Inc. bc-csharp legion_of_the_bouncy_castle:bc_csharp (from the name) | before 2.7.0 | CNA record |
References
- https://github.com/bcgit/bc-csharp/wiki/CVE-2026-103602vendor-advisory
- https://github.com/bcgit/bc-csharp/commit/f196a22bbf7765cc19b0c4f4645c74ea7ad35e09patch
- https://github.com/bcgit/bc-csharp/commit/be276e057775a6a674a62e9d9a2583b229978f73patch
- https://github.com/bcgit/bc-csharp/commit/75c3c576602886180ed92a63c89419e3bd63b392patch
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.