CVE-2026-16000
HIGHDescription
Missing cryptographic step in the DSTU 7624 CCM mode implementation (KCcmBlockCipher) in Legion of the Bouncy Castle Inc. bc-csharp before 2.7.0 allows an attacker who can observe encrypted messages of known or chosen content to forge ciphertexts with valid authentication tags, via messages encrypted without associated data. The cause is that the G1 block, which binds the nonce, the message length and the parameter flags into the CBC-MAC, was processed only when associated data was present. Without associated data the tag was a CBC-MAC of the plaintext alone, independent of the nonce. Only applications that use KCcmBlockCipher directly and supply no associated data are affected.
How to fix
TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works
Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.
CVSS v3 Vector
Exploitability
Impact
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Exploit Intelligence
Low risk: more likely to be exploited than 13% of all known CVEs.
References
Related Vulnerabilities
Other CWE-325 vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2021-22946 | High | 7.5 | 4.5% | - | Fix |
| CVE-2020-15086 | Critical | 9.8 | 3.6% | - | Fix |
| CVE-2021-33560 | High | 7.5 | 2.4% | - | Fix |
| CVE-2020-15098 | High | 8.8 | 2.2% | - | Fix |
| CVE-2019-3738 | Medium | 6.5 | 1.7% | - | Fix |
| CVE-2016-9574 | Medium | 5.9 | 1.4% | - | Fix |
Common questions
How do I fix CVE-2026-16000?
Upgrade bc-csharp to 2.7.0 or later.
Is CVE-2026-16000 being actively exploited?
Not that we know of. CVE-2026-16000 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.22% is the estimated probability that it will be exploited in the next 30 days. That is higher than 13% of all scored CVEs.
How severe is CVE-2026-16000?
CVE-2026-16000 has a CVSS v3 base score of 7.5, rated high. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.
What does CVE-2026-16000 affect?
Published advisories record a fix for bc-csharp (NVD). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.
Embed a live status badge for CVE-2026-16000
Markdown
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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-10-27.