Quick answers
- Is CVE-2026-63574 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-63574 being exploited in the wild.
- How severe is CVE-2026-63574?
- Informational severity, published 2 October 2026.
- Which products and versions are affected?
- Legion of the Bouncy Castle BouncyCastle.Cryptography before 2.7.0.
- Is there a fix for CVE-2026-63574?
- Yes: fixed in BouncyCastle.Cryptography 2.7.0. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
- How is CVE-2026-63574 attacked?
- It is attacked over the network, in a software library.
- Am I affected by CVE-2026-63574?
- Check whether you run Legion of the Bouncy Castle 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: BouncyCastle.Cryptography 2.7.0
Technical details
The vulnerability exists in SignatureSubpacketsParser.ReadPacket and UserAttributeSubpacketsParser.ReadPacket, which parse OpenPGP subpacket headers using the five-octet length form without enforcing upper bounds or validating the declared length against the enclosing packet size. An attacker can craft an OpenPGP public key, certificate, or signature with a malicious subpacket header that declares an excessive allocation size; this requires no authentication or special preconditions. The result is denial of service via OutOfMemoryException or memory exhaustion. The fix is available in version 2.7.0.
Affected products
- Legion of the Bouncy Castle BouncyCastle.Cryptography before 2.7.0
Timeline
- 2026-10-02: disclosed