Quick answers
- Is CVE-2026-103601 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-103601 being exploited in the wild.
- How severe is CVE-2026-103601?
- 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-2026-103601?
- 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-2026-103601 attacked?
- It is attacked over the network, in a software library.
- Am I affected by CVE-2026-103601?
- 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: BouncyCastle.Cryptography 2.7.0
Technical details
The vulnerability resides in CCM and DSTU 7624 CCM AEAD implementations (CcmBlockCipher and KCcmBlockCipher). Decryption methods write plaintext to the caller-supplied output buffer before verifying the authentication tag; if tag verification fails, the plaintext is not cleared. An attacker can send forged ciphertexts and retrieve plaintext from failed decryptions if the buffer is reused or logged. Only decryption into caller-supplied buffers is affected; methods returning newly allocated arrays are safe.
Affected products
- Legion of the Bouncy Castle Inc. BouncyCastle.Cryptography before 2.7.0
Timeline
- 2026-10-02: disclosed
- 2026-10-02: patched