Quick answers
- Is CVE-2026-63569 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-63569 being exploited in the wild.
- How severe is CVE-2026-63569?
- Informational severity, published 2 October 2026.
- Which products and versions are affected?
- Legion of the Bouncy Castle Inc. BouncyCastle.Cryptography before 2.7.0.
- Is there a fix for CVE-2026-63569?
- Yes: fixed in 2.7.0. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
- How is CVE-2026-63569 attacked?
- It is attacked over the network, in a software library.
- Am I affected by CVE-2026-63569?
- Check whether you run Legion of the Bouncy Castle Inc. BouncyCastle.Cryptography at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
How to fix
- Fixed in: 2.7.0
Technical details
The vulnerability exists in DHAgreement.CalculateAgreement, which fails to apply range and subgroup-membership checks to ephemeral DH public key values. An on-path attacker can supply crafted small-order or out-of-range values that are then raised to the static private key without validation, defeating the key authentication guarantees of the MTI/A0 protocol and leaking the static private key modulo small factors of p-1, potentially recovering it entirely in groups with many such factors.
Affected products
- Legion of the Bouncy Castle Inc. BouncyCastle.Cryptography before 2.7.0
Timeline
- 2026-10-02: disclosed