CVE-2026-71889 Bouncy Castle - Broken Access Control

Bouncy Castle for Java < 1.86 and LTS < 2.73.13 contain a broken access control vulnerability caused by improper application of X.509 name constraints in PKIXCertPathReviewer, letting attackers bypass certificate path validation, exploit requires use of PKIXCertPathReviewer for trust decisions.

CVSS base score 8.7 /10
High
CISA KEV
Not listed
Public exploit
None known
Authentication
Not required
EPSS
0.17% chance of exploitation in 30 days
View the NVD record ↗

Details

Type
Broken Access Control
Impact
Broken Access Control
CVSS vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:Amber
Published
3 October 2026
Updated
15 October 2026
Weakness
CWE-295

Vendor fix

Update to Bouncy Castle for Java 1.86, LTS 2.73.13, or later versions.

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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