CVE-2026-17507 Bouncy Castle - Denial of Service

Bouncy Castle for Java < 1.86 contains a denial of service caused by signed integer misinterpretation of uint32 leaf_index in MLS implementation, letting attackers send crafted messages to exhaust JVM heap, exploit requires membership in group.

CVSS base score 7.5 /10
High
CISA KEV
Not listed
Public exploit
None known
Authentication
Not required
EPSS
0.32% chance of exploitation in 30 days
View the NVD record ↗

Details

Type
Denial of Service
Impact
Denial Of Service
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Published
2 October 2026
Updated
15 October 2026
Weakness
CWE-195

Vendor fix

Update to version 1.86 or later.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

References

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