Vulnerability · Published Aug 3, 2026 · Assigned by bcorg
CVE-2026-59641S/MIME validator trusts signer-asserted signingTime for path validation
High 8.7
In plain English
A high-severity insufficient verification of data authenticity in BC-FJA from Legion of the Bouncy Castle Inc.. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 7% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
In Bouncy Castle for Java before 1.85, S/MIME validator trusts signer-asserted signingTime for path validation. This issue also affects Bouncy Castle for Java LTS before 2.73.12, and Bouncy Castle for Java FIPS (BC-FJA) before bcmail-fips and bcjmail-fips 1.0.7 (1.0.X series), 2.0.7 (2.0.X series) and 2.1.7 (2.1.X series).
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | bouncycastle | no fix listed | DEBIAN-CVE-2026-59641 |
| Debian:13 | bouncycastle | no fix listed | DEBIAN-CVE-2026-59641 |
| Debian:14 | bouncycastle | 1.86-1 | DEBIAN-CVE-2026-59641 |
| Ubuntu:26.04:LTS | bouncycastle | no fix listed | UBUNTU-CVE-2026-59641 |
| Ubuntu:26.10 | bouncycastle | no fix listed | UBUNTU-CVE-2026-59641 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Legion of the Bouncy Castle Inc. | BC-JAVA | 0 – before 1.85 |
| Legion of the Bouncy Castle Inc. | BC-LTS-JAVA | 2.73.0 – before 2.73.12 |
| Legion of the Bouncy Castle Inc. | BC-FJA | 1.0.0 – before 1.0.72.0.0 – before 2.0.72.1.0 – before 2.1.7 |
| Legion of the Bouncy Castle Inc. | BC-FJA | 1.0.4 – before 1.0.72.0.0 – before 2.0.72.1.0 – before 2.1.7 |
Weakness: CWE-345 · 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/U:Amber