CVE-2026-59651
Description
A flaw was found in Bouncy Castle for Java. The BKS keystore, which is used for storing cryptographic keys, accepts legacy versions that utilize a 16-bit integrity Message Authentication Code (MAC) key. This weak integrity protection could allow an attacker to tamper with the keystore's contents without being detected, leading to a high integrity impact.
Statement
Bouncy Castle for Java is bundled as a cryptographic provider across numerous Red Hat products. The BKS keystore accepts legacy-format keystores protected by only a 16-bit integrity MAC key, weakening tamper detection and allowing undetected modification of keystore contents — a high integrity impact. Exploitation requires the application to load legacy-format BKS keystores.
Mitigation
Red Hat is not aware of a mitigation for this flaw other than updating the affected Bouncy Castle component to a fixed version (bc-java 1.85 or LTS 2.73.12) once available for the affected product.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 7.5 | 7.5 | N/A |
| Attack Vector | Network | Network | N/A |
| Attack Complexity | Low | Low | N/A |
| Privileges Required | None | None | N/A |
| User Interaction | None | None | N/A |
| Scope | Unchanged | Unchanged | N/A |
| Confidentiality | None | None | N/A |
| Integrity Impact | High | High | N/A |
| Availability Impact | None | None | N/A |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
NVD: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Understanding the Weakness (CWE)
Confidentiality
Technical Impact: Read Application Data
Incorrect usage of crypto primitives could render the supposedly encrypted data as unencrypted plaintext in the worst case.
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