High severity · published Aug 3, 2026
CVE-2026-59646
DTLS handshake reassembler allocates buffer from unchecked 24-bit length
7.5
CVSS
0.6%
EPSS
No
On KEV
Description
In Bouncy Castle for Java before 1.85, DTLS handshake reassembler allocates buffer from unchecked 24-bit length. This issue also affects Bouncy Castle for Java LTS before 2.73.12, and Bouncy Castle for Java FIPS (BC-FJA) before bctls-fips 1.0.24 (1.0.X series), 2.0.24 (2.0.X series) and 2.1.24 (2.1.X series).
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.6% · higher than 49% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
BC
BC-FJA · Legion of the Bouncy Castle Inc.
1.0.0 before 1.0.24; 2.0.0 before 2.0.24; 2.1.0 before 2.1.24 · source: vendor
BC
BC-JAVA · Legion of the Bouncy Castle Inc.
before 1.85 · source: vendor, NVD
BC
BC-LTS-JAVA · Legion of the Bouncy Castle Inc.
2.73.0 before 2.73.12 · source: vendor
BC
Bctls-fips · Bouncycastle
before 1.0.24; 2.0.19 before 2.0.24; 2.1.20 before 2.1.24 · source: NVD
BC
Bouncy Castle For Java Lts · Bouncycastle
through 2.73.11 · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-59646
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-59646
Patch
https://github.com/bcgit/bc-java/commit/2d98721e71bbd822ffa0f84e088eea645cf679fa
Patch
https://github.com/bcgit/bc-java/commit/2ea38942c7917f6d7ab4de93d8a5336d021df0d9
Third Party Advisory
https://github.com/bcgit/bc-java/wiki/CVE%E2%80%902026%E2%80%9059646
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