CVE-2026-63568: Unbounded CMP/CRMF password-based MAC iteration count allows CPU exhaustion
Legion of the Bouncy Castle Inc. · bc-csharp
Fixed in 2.7.0 · Affected: Legion of the Bouncy Castle Inc. bc-csharp before 2.7.0 · Exploitation: unlikely (under 1%)
Not in CyberSIXT coverage yet: no article names this CVE. This page shows the public record.
Higher than 30% of scored CVEs
DescriptionCVE.org
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.
Affected products1
From the CVE record. A product or version that is not listed is unknown, not unaffected.
- Legion of the Bouncy Castle Inc. · bc-csharpbefore 2.7.0
On the Atlas
Every published CVE is on the CyberSIXT Atlas, grouped by weakness, vendor and month.
- Exploitation
- Unlikely (under 1%). EPSS under 1%, or no score yet.
- CISA KEV
- Not listed
- Public check
- No public nuclei template
- Published
- October 2026
CoverageNo articles yet
No CyberSIXT article names CVE-2026-63568 yet, so there is no coverage timeline, action brief or change log for it. Everything on this page comes from the public CVE record, CISA KEV, EPSS and the nuclei template index. Search the archive or see the CVEs in the news.