Netty: Missing CertificateID Validation in OCSP Response Allows Replay Attacks
Summary
| CVE | CVE-2026-56820 |
|---|---|
| State | PUBLISHED |
| Assigner | GitHub_M |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-07-21 23:17:52 UTC |
| Updated | 2026-07-22 20:35:40 UTC |
| Description | 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. |
Risk And Classification
Primary CVSS: v3.1 7.4 HIGH from [email protected]
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
EPSS: 0.002960000 probability, percentile 0.217270000 (date 2026-07-22)
Problem Types: CWE-295 | CWE-295 CWE-295: Improper Certificate Validation
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 3.1 | [email protected] | Secondary | 7.4 | HIGH | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N |
| 3.1 | CNA | DECLARED | 7.4 | HIGH | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N |
CVSS v3.1 Breakdown
Attack Vector
NetworkAttack Complexity
HighPrivileges Required
NoneUser Interaction
NoneScope
UnchangedConfidentiality
HighIntegrity
HighAvailability
NoneCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
Vendor Declared Affected Products
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| github.com/netty/netty/releases/tag/netty-4.1.136.Final | [email protected] | github.com | |
| github.com/netty/netty/commit/5b68c61f37aa4a3045cba624cbea239655c9003b | [email protected] | github.com | |
| github.com/netty/netty/releases/tag/netty-4.2.16.Final | [email protected] | github.com | |
| github.com/netty/netty/commit/bb2ff68a1fb71cb4b0eb9a9e17b66c52aff680c6 | [email protected] | github.com | |
| github.com/netty/netty/security/advisories/GHSA-272m-gcwp-mpwg | [email protected] | github.com | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
No vendor comments have been submitted for this CVE.
There are currently no legacy QID mappings associated with this CVE.