CVSS 3.1
7.4 highCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:NCVE-2026-56821
High (7.4) in netty netty. EPSS 0.2% chance of exploitation in the next 30 days. Fixed in io.netty:netty-handler-ssl-ocsp 4.1.136.Final, 4.2.16.Final.
Netty is an asynchronous, event-driven network application framework. Prior to versions 4.1.136.Final and 4.2.16.Final, the OcspServerCertificateValidator flags an out-of-date OCSP response but does not stop processing it, so an expired GOOD response is still reported as VALID, letting an on-path attacker replay a stale GOOD response to bypass revocation of a since-revoked certificate. Exploitation can lead to certificate revocation bypass via replay of an expired OCSP response. Any application using OcspServerCertificateValidator is affected; a revoked certificate can be accepted. This issue has been fixed in versions 4.1.136.Final and 4.2.16.Final.
Severity
- EPSS
- 0.2% chance of exploitation in the next 30 days; higher than 12% of CVEs (scores of 2026-10-31)
- CWE
- CWE-299
- Published
- Modified
- Record from
- the NVD, synced
Affected
- netty:netty
Packages (OSV)
| Advisory | Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|---|
| GHSA-g7hg-vrcf-mvmr | Maven | io.netty:netty-handler-ssl-ocsp | >=4.2.0.Final <4.2.16.Final | 4.2.16.Final |
| GHSA-g7hg-vrcf-mvmr | Maven | io.netty:netty-handler-ssl-ocsp | <4.1.136.Final | 4.1.136.Final |