PT-2026-63259 · Netty · Netty

CVE-2026-56820 · Published 2026-07-21 · Updated 2026-07-21

Mitre

CVSS v3.1

7.4

High

Base vector

AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

Netty is a network application framework for development of protocol servers and clients. In versions 4.2.0.Final through 4.2.15.Final and prior to 4.1.135.Final, OcspClient does not validate that the CertificateID in an OCSP response matches the requested CertificateID, which can lead to replay attack. OcspClient.validateResponse accepts a legitimately signed GOOD status response for an unrelated certificate issued by the same CA, allowing bypass of revocation checks for another certificate. This issue is fixed in versions 4.1.136.Final and 4.2.16.Final.

Fix

Improper Certificate Validation

Weakness Enumeration

CWE-295

Related Identifiers

CVE-2026-56820

Affected Products

Netty

References · 6

• https://nvd.nist.gov/vuln/detail/CVE-2026-56820 · Security Note
• https://github.com/netty/netty/security/advisories/GHSA-272m-gcwp-mpwg · Note
• https://github.com/netty/netty/releases/tag/netty-4.1.136.Final · Note
• https://github.com/netty/netty/commit/bb2ff68a1fb71cb4b0eb9a9e17b66c52aff680c6 · Note
• https://github.com/netty/netty/commit/5b68c61f37aa4a3045cba624cbea239655c9003b · Note
• https://github.com/netty/netty/releases/tag/netty-4.2.16.Final · Note