CVE-2026-63576
HIGH
MEDIUM
Priority: 0.02
BB Relevance:
76/100
Published: 2026-10-02
Modified: 2026-10-28
First seen: 2026-10-29
Status: active
Attack Surface
Network
Low Complexity
No Auth
No Interaction
Integ. Impact
CVSS Vector Breakdown
AV:
Network
AC:
Low
PR:
None
UI:
None
S:
X
AT:
Present
VC:
None
VI:
High
VA:
None
Description
Improper certificate validation in PkixNameConstraintValidator (ExtractHostFromURL) in Legion of the Bouncy Castle Inc. bc-csharp before 2.7.0 allows a name-constrained subordinate CA, or anyone able to obtain certificates with chosen subjectAltName URIs from such a CA, to bypass permitted or excluded uniformResourceIdentifier name constraints during certification path validation via a URI whose path, query, fragment or userinfo contains characters such as '@' or ':', because the host was extracted by string slicing without first isolating the RFC 3986 authority component, so the host compared against the constraints could differ from the URI's actual host.
Weakness Classification (1)
Affected Software (2)
| Vendor | Product | Version |
|---|---|---|
| bouncycastle | bc-csharp | < 2.7.0 |
| bouncycastle | bc-csharp | < 2.7.0 |
References & Advisories (2)
Patch
Vendor Advisory
Patch