CVE-2026-103601: Release of Unverified Plaintext
Source GCVE Database
Not known to be exploited · CVSS 8.2 High : upgrade to 2.7.0 soon.
Data as of 28 Oct 2026, 17:11 UTC
- EPSS
- 0.3% chance of exploitation in 30 days – higher than 25% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 2.7.0
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/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
Since the vulnerability affects versions before 2.7.0, upgrading to version 2.7.0 or later (if available) is recommended once confirmed. Until then, avoid using decryption methods that write plaintext into caller-supplied buffers or ensure that output buffers from failed decryptions are not exposed or logged. Monitor the vendor's advisory for official remediation guidance and patches.
Description
A vulnerability in the CCM and DSTU 7624 CCM AEAD modes of the Legion of the Bouncy Castle Inc. bc-csharp library before version 2.7.0 allows remote attackers to obtain plaintext from failed decryptions. This occurs because the decryption process writes recovered plaintext into a caller-supplied output buffer before verifying the authentication tag, leaving the plaintext accessible if the tag check fails. Only decryption methods using caller-supplied buffers are affected; methods returning newly allocated arrays are not vulnerable.
References
- nvd.nist.gov/vuln/detail/CVE-2026-103601 (opens in a new tab)
- github.com/bcgit/bc-csharp/commit/4ddb1d0bfeae3a81b18f4446d8cc8a7871bd2d9f (opens in a new tab)
- github.com/bcgit/bc-csharp/commit/e0868323645a063cb2479646e93c1449dc338de5 (opens in a new tab)
- github.com/bcgit/bc-csharp/wiki/CVE-2026-103601 (opens in a new tab)