CVE-2026-16000: Legion of · Missing Cryptographic Step
Source GCVE Database
Not known to be exploited · CVSS 8.7 High : upgrade to 2.7.0 soon.
Data as of 27 Oct 2026, 20:15 UTC
- Patch
- Available – fixed in 2.7.0
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:NExploitation evidence
Disclosed: evidence found.
CVE published 2 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Upgrade bc-csharp and BouncyCastle.Cryptography to 2.7.0.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| Legion of the Bouncy Castle Inc.bc-csharp | Affected
| Fixed in
|
NuGetBouncyCastle.Cryptographypkg:nuget/BouncyCastle.CryptographyOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
A fix is available in Bouncy Castle bc-csharp version 2.7.0 and later. Users should upgrade to version 2.7.0 or newer to remediate this vulnerability. Until then, avoid using KCcmBlockCipher without associated data. No other mitigation is indicated.
Description
A vulnerability in the DSTU 7624 CCM mode implementation (KCcmBlockCipher) in Bouncy Castle bc-csharp before version 2.7.0 allows attackers to forge ciphertexts with valid authentication tags when no associated data is used. This occurs because a critical cryptographic step binding the nonce, message length, and parameter flags into the CBC-MAC was skipped if associated data was absent, causing the authentication tag to be independent of the nonce. Only applications using KCcmBlockCipher directly without associated data are affected.