Name: CVE-2026-59639: Improper Verification of Cryptographic Signature
Creator: Rapid7
Published: 2026-08-03T00:00:00.000Z
License: https://www.rapid7.com/legal/website-terms-of-use/
Keywords: CVE, CVE-2026-59639, CWE-347, CVSS 7.5, EPSS 0.00242

In Bouncy Castle for Java before 1.85, CMS verifySignatures returns true for SignedData with zero signers. This issue also affects Bouncy Castle for Java LTS before 2.73.12, and Bouncy Castle for Java FIPS (BC-FJA) before bcpkix-fips 1.0.12 (1.0.X series), 2.0.12 (2.0.X series) and 2.1.12 (2.1.X series).

CVSS Details

CVSS 4.0 Base Score: 8.7 (HIGH)
CVSS 4.0 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)
CVSS 3.1 Base Score: 7.5
CVSS 3.1 Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N)

Covered by Rapid7

Product	Vendor Advisory	Solution File	Added	Published
Atlassian Jira	—	Upgrade to the latest version of Atlassian JIRA	Sep 16, 2026	Sep 15, 2026
Redhat_linux	—	—	Aug 26, 2026	Aug 3, 2026

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CVSS Details

Covered by Rapid7

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