CVE-2026-5598
Description
A flaw was found in Legion of the Bouncy Castle Inc. BC-JAVA core. A covert timing channel vulnerability, caused by non-constant time comparisons, risks the leakage of private keys in the FrodoKEM implementation. An unauthenticated, remote attacker can potentially exploit this timing discrepancy to gain unauthorized access to sensitive cryptographic information.
Statement
To exploit this issue, an unauthenticated attacker needs to send highly specific, malformed ciphertexts to the target server. These payloads are used to interact with the private key of the server in a way that the vulnerable, non-constant time code paths are triggered during the verification step. An attack typically requires sending a large volume of these requests to perform statistical analysis on the resulting timing variations, increasing its complexity. The primary security impact of this vulnerability is the potential leakage of private keys associated with the FrodoKEM implementation. This can compromise encrypted communications or authentication mechanisms.
Mitigation
To mitigate this vulnerability, implement aggressive rate limiting and anomaly detection, specifically looking for unusual, high-frequency cryptographic handshake failures or anomalous traffic patterns targeting endpoints that handle key exchanges in the network logs.
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).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 7.5 | N/A | 7.5 |
| Attack Vector | Network | N/A | Network |
| Attack Complexity | Low | N/A | Low |
| Privileges Required | None | N/A | None |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | High | N/A | High |
| Integrity Impact | None | N/A | None |
| Availability Impact | None | N/A | None |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
cve.org: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Understanding the Weakness (CWE)
Confidentiality,Other
Technical Impact: Read Application Data; Other
Information exposure.
Frequently Asked Questions
Not sure what something means? Check out our Security Glossary.
Want to get errata notifications? Sign up here.
