Excessive Iteration Affecting org.bouncycastle:bcmls-debug-jdk18on package, versions [,1.85)
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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- published4 Aug 2026
- disclosed3 Aug 2026
- creditUnknown
Introduced: 3 Aug 2026
NewCVE-2026-59644 (opens in a new tab)How to fix?
Upgrade org.bouncycastle:bcmls-debug-jdk18on to version 1.85 or higher.
Overview
Affected versions of this package are vulnerable to Excessive Iteration in the HashRatchet.get(int generation) method of GroupKeySet, reached through PrivateMessage.unprotect(), which loops while (nextGeneration < generation) next(); and caches every intermediate KeyGeneration in an unbounded HashMap. A user who is an authenticated group member can force every other member to run roughly 2 billion HKDF iterations and allocate multiple gigabytes of cache memory by sending an MLS PrivateMessage whose sender generation field is set to 0x7FFFFFFF. The generation value is processed after only a hasLeaf() check and before any per-message signature verification, and it is carried in sender data encrypted under shared group secrets, so exploitation requires valid membership in the group.