Netty up to 4.1.134.Final/4.2.15.Final OcspClient OcspClient.validateResponse certificate validation

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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3.6$0-$5k0.66

Summaryinfo

A vulnerability marked as problematic has been reported in Netty up to 4.1.134.Final/4.2.15.Final. Affected is the function OcspClient.validateResponse of the component OcspClient. Performing a manipulation results in certificate validation. This vulnerability is cataloged as CVE-2026-56820. It is possible to initiate the attack remotely. There is no exploit available.

Detailsinfo

A vulnerability was found in Netty up to 4.1.134.Final/4.2.15.Final. It has been classified as problematic. This affects the function OcspClient.validateResponse of the component OcspClient. The manipulation with an unknown input leads to a certificate validation vulnerability. CWE is classifying the issue as CWE-295. The product does not validate, or incorrectly validates, a certificate. This is going to have an impact on integrity. The summary by CVE is:

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.

The advisory is shared at github.com. This vulnerability is uniquely identified as CVE-2026-56820 since 06/23/2026. The exploitability is told to be difficult. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. Technical details are known, but no exploit is available. MITRE ATT&CK project uses the attack technique T1587.003 for this issue.

Upgrading to version 4.1.136.Final or 4.2.16.Final eliminates this vulnerability.

If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Productinfo

Name

Version

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 3.7
VulDB Meta Temp Score: 3.6

VulDB Base Score: 3.7
VulDB Temp Score: 3.6
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Certificate validation
CWE: CWE-295 / CWE-287
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: no mitigation known
Status: 🔍

0-Day Time: 🔒

Upgrade: Netty 4.1.136.Final/4.2.16.Final

Timelineinfo

06/23/2026 CVE reserved
07/22/2026 +29 days Advisory disclosed
07/22/2026 +0 days VulDB entry created
07/22/2026 +0 days VulDB entry last update

Sourcesinfo

Product: github.com

Advisory: github.com
Status: Confirmed

CVE: CVE-2026-56820 (🔒)
GCVE (CVE): GCVE-0-2026-56820
GCVE (VulDB): GCVE-100-382029

Entryinfo

Created: 07/22/2026 07:43
Changes: 07/22/2026 07:43 (53)
Complete: 🔍
Cache ID: 216::103

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