CVE-2026-59640
Description
A flaw was found in Bouncy Castle for Java. A remote attacker can exploit an OpenPGP (Open Pretty Good Privacy) Cipher Feedback (CFB) quick-check oracle vulnerability. This oracle, active on symmetric and session-key paths, could allow an attacker to gain sensitive information by observing the results of cryptographic operations. This could lead to the disclosure of confidential data.
Statement
Bouncy Castle for Java is bundled as a cryptographic provider in Red Hat middleware products. An OpenPGP CFB "quick-check" oracle active on the symmetric and session-key paths lets a remote attacker infer plaintext or key material by observing the results of cryptographic operations, leading to disclosure of confidential data. This is reachable via OpenPGP (bcpg) decryption of attacker-influenced data.
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, LTS 2.73.12, or BC-FJA bcpg-fips 1.0.13/2.0.13/2.1.13) 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 | 5.3 | 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 | High | Low | N/A |
| Integrity Impact | None | None | 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:H/I:N/A:N
NVD: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
Understanding the Weakness (CWE)
Confidentiality,Access Control
Technical Impact: Read Application Data; Bypass Protection Mechanism
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