CVE-2026-77696
Description
A flaw was found in OpenSSL. During SM2 signature generation, variable-time arithmetic operations are performed on secret values, creating an observable timing side-channel. An attacker capable of measuring signature generation times can collect timing data across multiple signing operations, which may allow them to recover the private key.
Statement
This issue is rated Moderate because SM2 signature generation can leak timing information about the secret nonce, which with many measurements may enable private-key recovery. Exploitation requires observing fine-grained signing times for SM2 operations and is not relevant when SM2 is unused.
Mitigation
If SM2 is not required, disable or avoid SM2 signing in application configuration. Where SM2 must be used, restrict who can solicit large numbers of signatures.
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 | 5.9 | N/A | 3.7 |
| Attack Vector | Network | N/A | Network |
| Attack Complexity | High | N/A | High |
| Privileges Required | None | N/A | None |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | High | N/A | Low |
| Integrity Impact | None | N/A | None |
| Availability Impact | None | N/A | None |
Vector
Red Hat: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
cve.org: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N
Frequently Asked Questions
Not sure what something means? Check out our Security Glossary.
Want to get errata notifications? Sign up here.
