CVE-2026-85515
Description
A flaw was found in Bouncy Castle. When processing truncated OpenPGP encrypted messages, the library incorrectly treats premature stream termination as a normal end of message and fails to perform required integrity checks. A remote attacker could exploit this flaw by tampering with or truncating encrypted messages in transit, causing applications to accept modified or unauthenticated plaintext without raising an error.
Statement
This vulnerability is rated as Moderate severity because successful exploitation depends on strict message length constraints and requires an adversary positioned to manipulate network traffic in transit. Within Red Hat products embedding Bouncy Castle, applications streaming OpenPGP data through high-level APIs may consume incomplete ciphertext sequences without triggering cryptographic authentication checks. However, low-level decryption routines that explicitly enforce integrity verification remain unaffected, limiting the overall attack surface across typical deployments.
Mitigation
Upgrade to Bouncy Castle for Java bcpg 1.86 (or BC-LTS 2.73.13 / BC-FJA bcpg-fips 1.0.14, 2.0.14.1, 2.1.14 as applicable); as a workaround, use the low-level API or whole-chunk readers, which are unaffected, and reject truncated OpenPGP messages.
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 | 5.9 | N/A | N/A |
| Attack Vector | Network | N/A | N/A |
| Attack Complexity | High | N/A | N/A |
| Privileges Required | None | N/A | N/A |
| User Interaction | None | N/A | N/A |
| Scope | Unchanged | N/A | N/A |
| Confidentiality | None | N/A | N/A |
| Integrity Impact | High | N/A | N/A |
| Availability Impact | None | N/A | N/A |
Vector
Red Hat: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N
Understanding the Weakness (CWE)
Integrity,Other
Technical Impact: Modify Application Data; Other
Integrity checks usually use a secret key that helps authenticate the data origin. Skipping integrity checking generally opens up the possibility that new data from an invalid source can be injected.
Integrity,Other
Technical Impact: Other
Data that is parsed and used may be corrupted.
Non-Repudiation,Other
Technical Impact: Hide Activities; Other
Without a checksum check, it is impossible to determine if any changes have been made to the data after it was sent.
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