CVE-2026-12852: Legion of the Bouncy Castle BC-JAVA · Excessive Memory Allocation
Affects Legion of the Bouncy Castle BC-JAVASource CVE Database V5
Not known to be exploited · CVSS 8.7 High : upgrade to 1.85 soon.
Data as of 26 Oct 2026, 12:29 UTC
- EPSS
- 0.4% chance of exploitation in 30 days – higher than 42% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- CISA SSVC
- Exploitation
- No evidence of active exploitation and no public proof of concept
- Automatable
- Attackers can reliably automate steps 1–4 of the kill chain
- Technical impact
- Limited control over the software or limited information exposure
CISA SSVC assessment, 2026-08-03.
- Patch
- Available – fixed in 1.85
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/U:AmberExploitation evidence
Disclosed: evidence found.
CVE published 3 Aug 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-JAVA and Legion of the Bouncy Castle Inc./bcmls to 1.85.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| Legion of the Bouncy Castle Inc.BC-JAVA | Affected
| Fixed in
|
MavenLegion of the Bouncy Castle Inc./bcmlspkg:maven/Legion of the Bouncy Castle Inc./bcmlsOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
Description
In Bouncy Castle for Java before 1.85, MLS wire decoder allocates attacker-declared opaque length before bounds check.