CVE-2026-63568
Allocation of resources without limits or throttling in the CMP/CRMF password-based MAC verifier…
- Risk score
- 62/100
- CVSS
- 8.7 v4.0
- Exploit chance (30 days)
- 0.3%
- Published
- 2 Oct 2026
Open in the live forecast Today's forecast
What to know
- What it is
- Allocation of resources without limits or throttling in the CMP/CRMF password-based MAC verifier (PKMacBuilder) in Legion of the Bouncy Castle Inc. bc-csharp before 2.7.0 allows a remote unauthenticated attacker to cause a denial of service through CPU exhaustion via a CMP message or CRMF certificate request whose PBM…
- Affected
- See advisory
- Fix
- Upgrade the product to 2.7.0 or later.
- Exploitation
- No known exploitation
Why it is Amber
- CVSS 8.7 high
- Remotely exploitable without logging in
References
- https://github.com/bcgit/bc-csharp/commit/10a9862fad04bb0c832a78b10e71d9818d6d1a63
- https://github.com/bcgit/bc-csharp/commit/65283bae66843d0d3c13c5e0272dbbe1c0d6aa04
- https://github.com/bcgit/bc-csharp/commit/d16f08a53dd0a78eb3310bbe80c947c7e1677290
- https://github.com/bcgit/bc-csharp/wiki/CVE-2026-63568
Original description
Allocation of resources without limits or throttling in the CMP/CRMF password-based MAC verifier (PKMacBuilder) in Legion of the Bouncy Castle Inc. bc-csharp before 2.7.0 allows a remote unauthenticated attacker to cause a denial of service through CPU exhaustion via a CMP message or CRMF certificate request whose PBMParameter declares a very large iteration count, because PKMacBuilder enforced its iteration-count ceiling only when the caller had supplied an explicit maximum through the PKMacBuilder(IPKMacPrimitivesProvider, int) constructor. With any other constructor, ProtectedPkiMessage.Verify and CertificateRequestMessage.IsValidSigningKeyPop performed as many hash iterations as the sender requested, up to about 2^31, before the MAC could be checked.
Last activity 2 Oct 2026. Patch Forecast updates every hour.