CVE-2026-56820 (GCVE-0-2026-56820)

Vulnerability from cvelistv5 – Published: 2026-07-21 22:26 – Updated: 2026-07-21 22:26
VLAI
Title
Netty: Missing CertificateID Validation in OCSP Response Allows Replay Attacks
Summary
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.
Severity
7.4 (High)
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
CWE
  • CWE-295 - Improper Certificate Validation
Assigner
References
Impacted products
Vendor Product Version
netty netty Affected: >= 4.2.0.Final, < 4.2.16.Final
Affected: < 4.1.136.Final
Create a notification for this product.
Show details on NVD website
To clipboard 

{
  "containers": {
    "cna": {
      "affected": [
        {
          "product": "netty",
          "vendor": "netty",
          "versions": [
            {
              "status": "affected",
              "version": "\u003e= 4.2.0.Final, \u003c 4.2.16.Final"
            },
            {
              "status": "affected",
              "version": "\u003c 4.1.136.Final"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "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."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "HIGH",
            "attackVector": "NETWORK",
            "availabilityImpact": "NONE",
            "baseScore": 7.4,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "HIGH",
            "integrityImpact": "HIGH",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-295",
              "description": "CWE-295: Improper Certificate Validation",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-07-21T22:26:16.588Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/netty/netty/security/advisories/GHSA-272m-gcwp-mpwg",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/netty/netty/security/advisories/GHSA-272m-gcwp-mpwg"
        },
        {
          "name": "https://github.com/netty/netty/commit/5b68c61f37aa4a3045cba624cbea239655c9003b",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/netty/netty/commit/5b68c61f37aa4a3045cba624cbea239655c9003b"
        },
        {
          "name": "https://github.com/netty/netty/commit/bb2ff68a1fb71cb4b0eb9a9e17b66c52aff680c6",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/netty/netty/commit/bb2ff68a1fb71cb4b0eb9a9e17b66c52aff680c6"
        },
        {
          "name": "https://github.com/netty/netty/releases/tag/netty-4.1.136.Final",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/netty/netty/releases/tag/netty-4.1.136.Final"
        },
        {
          "name": "https://github.com/netty/netty/releases/tag/netty-4.2.16.Final",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/netty/netty/releases/tag/netty-4.2.16.Final"
        }
      ],
      "source": {
        "advisory": "GHSA-272m-gcwp-mpwg",
        "discovery": "UNKNOWN"
      },
      "title": "Netty: Missing CertificateID Validation in OCSP Response Allows Replay Attacks"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-56820",
    "datePublished": "2026-07-21T22:26:16.588Z",
    "dateReserved": "2026-06-23T14:55:09.116Z",
    "dateUpdated": "2026-07-21T22:26:16.588Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.





Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.