GCVE Workshop - 22 September 2026 (14:00-18:00), Luxembourg Before The Vulnopticon Conference - Registration

CVE-2026-22703 (GCVE-0-2026-22703)

Vulnerability from cvelistv5 – Published: 2026-01-10 06:11 – Updated: 2026-01-12 16:43
VLAI
Title
Cosign verification accepts any valid Rekor entry under certain conditions
Summary
Cosign provides code signing and transparency for containers and binaries. Prior to versions 2.6.2 and 3.0.4, Cosign bundle can be crafted to successfully verify an artifact even if the embedded Rekor entry does not reference the artifact's digest, signature or public key. When verifying a Rekor entry, Cosign verifies the Rekor entry signature, and also compares the artifact's digest, the user's public key from either a Fulcio certificate or provided by the user, and the artifact signature to the Rekor entry contents. Without these comparisons, Cosign would accept any response from Rekor as valid. A malicious actor that has compromised a user's identity or signing key could construct a valid Cosign bundle by including any arbitrary Rekor entry, thus preventing the user from being able to audit the signing event. This issue has been patched in versions 2.6.2 and 3.0.4.
Severity
5.5 (Medium)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N
SSVC
Exploitation: none Automatable: no Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-01-12 16:43 UTC
CWE
  • CWE-345 - Insufficient Verification of Data Authenticity
Assigner
References
Impacted products
Vendor Product Version CPE status
sigstore cosign Affected: < 3.0.4
Affected: < 2.6.2
guessed Create a notification for this product.
Show details on NVD website
To clipboard 

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-22703",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-01-12T16:43:50.752285Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-01-12T16:43:57.302Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "cosign",
          "vendor": "sigstore",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 3.0.4"
            },
            {
              "status": "affected",
              "version": "\u003c 2.6.2"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "Cosign provides code signing and transparency for containers and binaries. Prior to versions 2.6.2 and 3.0.4, Cosign bundle can be crafted to successfully verify an artifact even if the embedded Rekor entry does not reference the artifact\u0027s digest, signature or public key. When verifying a Rekor entry, Cosign verifies the Rekor entry signature, and also compares the artifact\u0027s digest, the user\u0027s public key from either a Fulcio certificate or provided by the user, and the artifact signature to the Rekor entry contents. Without these comparisons, Cosign would accept any response from Rekor as valid. A malicious actor that has compromised a user\u0027s identity or signing key could construct a valid Cosign bundle by including any arbitrary Rekor entry, thus preventing the user from being able to audit the signing event. This issue has been patched in versions 2.6.2 and 3.0.4."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "LOCAL",
            "availabilityImpact": "NONE",
            "baseScore": 5.5,
            "baseSeverity": "MEDIUM",
            "confidentialityImpact": "NONE",
            "integrityImpact": "HIGH",
            "privilegesRequired": "LOW",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-345",
              "description": "CWE-345: Insufficient Verification of Data Authenticity",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-01-10T06:11:09.426Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/sigstore/cosign/security/advisories/GHSA-whqx-f9j3-ch6m",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/sigstore/cosign/security/advisories/GHSA-whqx-f9j3-ch6m"
        },
        {
          "name": "https://github.com/sigstore/cosign/pull/4623",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/sigstore/cosign/pull/4623"
        },
        {
          "name": "https://github.com/sigstore/cosign/commit/6832fba4928c1ad69400235bbc41212de5006176",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/sigstore/cosign/commit/6832fba4928c1ad69400235bbc41212de5006176"
        }
      ],
      "source": {
        "advisory": "GHSA-whqx-f9j3-ch6m",
        "discovery": "UNKNOWN"
      },
      "title": "Cosign verification accepts any valid Rekor entry under certain conditions"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-22703",
    "datePublished": "2026-01-10T06:11:09.426Z",
    "dateReserved": "2026-01-08T19:23:09.857Z",
    "dateUpdated": "2026-01-12T16:43:57.302Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-22703",
      "date": "2026-09-08",
      "epss": "0.00097",
      "percentile": "0.00806"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-22703\",\"sourceIdentifier\":\"security-advisories@github.com\",\"published\":\"2026-01-10T07:16:03.030\",\"lastModified\":\"2026-06-17T10:20:15.880\",\"vulnStatus\":\"Analyzed\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"Cosign provides code signing and transparency for containers and binaries. Prior to versions 2.6.2 and 3.0.4, Cosign bundle can be crafted to successfully verify an artifact even if the embedded Rekor entry does not reference the artifact\u0027s digest, signature or public key. When verifying a Rekor entry, Cosign verifies the Rekor entry signature, and also compares the artifact\u0027s digest, the user\u0027s public key from either a Fulcio certificate or provided by the user, and the artifact signature to the Rekor entry contents. Without these comparisons, Cosign would accept any response from Rekor as valid. A malicious actor that has compromised a user\u0027s identity or signing key could construct a valid Cosign bundle by including any arbitrary Rekor entry, thus preventing the user from being able to audit the signing event. This issue has been patched in versions 2.6.2 and 3.0.4.\"},{\"lang\":\"es\",\"value\":\"Cosign proporciona firma de c\u00f3digo y transparencia para contenedores y binarios. Antes de las versiones 2.6.2 y 3.0.4, un paquete de Cosign pod\u00eda ser manipulado para verificar con \u00e9xito un artefacto incluso si la entrada de Rekor incrustada no hac\u00eda referencia al *digest* del artefacto, a la firma o a la clave p\u00fablica. Al verificar una entrada de Rekor, Cosign verifica la firma de la entrada de Rekor y tambi\u00e9n compara el *digest* del artefacto, la clave p\u00fablica del usuario (ya sea de un certificado de Fulcio o proporcionada por el usuario) y la firma del artefacto con el contenido de la entrada de Rekor. Sin estas comparaciones, Cosign aceptar\u00eda cualquier respuesta de Rekor como v\u00e1lida. Un actor malicioso que haya comprometido la identidad o la clave de firma de un usuario podr\u00eda construir un paquete de Cosign v\u00e1lido incluyendo cualquier entrada de Rekor arbitraria, impidiendo as\u00ed al usuario auditar el evento de firma. Este problema ha sido parcheado en las versiones 2.6.2 y 3.0.4.\"}],\"affected\":[{\"source\":\"security-advisories@github.com\",\"affectedData\":[{\"vendor\":\"sigstore\",\"product\":\"cosign\",\"versions\":[{\"version\":\"\u003c 3.0.4\",\"status\":\"affected\"},{\"version\":\"\u003c 2.6.2\",\"status\":\"affected\"}]}]}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"security-advisories@github.com\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N\",\"baseScore\":5.5,\"baseSeverity\":\"MEDIUM\",\"attackVector\":\"LOCAL\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"LOW\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"NONE\",\"integrityImpact\":\"HIGH\",\"availabilityImpact\":\"NONE\"},\"exploitabilityScore\":1.8,\"impactScore\":3.6},{\"source\":\"nvd@nist.gov\",\"type\":\"Primary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N\",\"baseScore\":5.5,\"baseSeverity\":\"MEDIUM\",\"attackVector\":\"LOCAL\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"LOW\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"NONE\",\"integrityImpact\":\"HIGH\",\"availabilityImpact\":\"NONE\"},\"exploitabilityScore\":1.8,\"impactScore\":3.6}],\"ssvcV203\":[{\"source\":\"134c704f-9b21-4f2e-91b3-4a467353bcc0\",\"ssvcData\":{\"timestamp\":\"2026-01-12T16:43:50.752285Z\",\"id\":\"CVE-2026-22703\",\"options\":[{\"exploitation\":\"none\"},{\"automatable\":\"no\"},{\"technicalImpact\":\"partial\"}],\"role\":\"CISA Coordinator\",\"version\":\"2.0.3\"}}]},\"weaknesses\":[{\"source\":\"security-advisories@github.com\",\"type\":\"Secondary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-345\"}]}],\"configurations\":[{\"nodes\":[{\"operator\":\"OR\",\"negate\":false,\"cpeMatch\":[{\"vulnerable\":true,\"criteria\":\"cpe:2.3:a:sigstore:cosign:*:*:*:*:*:*:*:*\",\"versionEndExcluding\":\"2.6.2\",\"matchCriteriaId\":\"7ABA7B55-66EA-4E85-9F5E-1C392C4FCB6C\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:a:sigstore:cosign:*:*:*:*:*:*:*:*\",\"versionStartIncluding\":\"3.0.0\",\"versionEndExcluding\":\"3.0.4\",\"matchCriteriaId\":\"35768783-8EF1-41DB-8DD1-6870B46B647C\"}]}]}],\"references\":[{\"url\":\"https://github.com/sigstore/cosign/commit/6832fba4928c1ad69400235bbc41212de5006176\",\"source\":\"security-advisories@github.com\",\"tags\":[\"Patch\"]},{\"url\":\"https://github.com/sigstore/cosign/pull/4623\",\"source\":\"security-advisories@github.com\",\"tags\":[\"Issue Tracking\"]},{\"url\":\"https://github.com/sigstore/cosign/security/advisories/GHSA-whqx-f9j3-ch6m\",\"source\":\"security-advisories@github.com\",\"tags\":[\"Exploit\",\"Vendor Advisory\"]}]}}",
    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-06-28T07:17:42+00:00",
      "cve": "CVE-2026-22703",
      "id": "CVE-2026-22703",
      "initial_release_date": "2026-01-10T06:11:09.426000+00:00",
      "product_status:known_affected": "35",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "github.com/sigstore/cosign: Cosign verification accepts any valid Rekor entry under certain conditions",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-22703.json",
      "version": "3"
    },
    "vulnrichment": {
      "containers": "{\"adp\": [{\"title\": \"CISA ADP Vulnrichment\", \"metrics\": [{\"other\": {\"type\": \"ssvc\", \"content\": {\"id\": \"CVE-2026-22703\", \"role\": \"CISA Coordinator\", \"options\": [{\"Exploitation\": \"none\"}, {\"Automatable\": \"no\"}, {\"Technical Impact\": \"partial\"}], \"version\": \"2.0.3\", \"timestamp\": \"2026-01-12T16:43:50.752285Z\"}}}], \"providerMetadata\": {\"orgId\": \"134c704f-9b21-4f2e-91b3-4a467353bcc0\", \"shortName\": \"CISA-ADP\", \"dateUpdated\": \"2026-01-12T16:43:54.654Z\"}}], \"cna\": {\"title\": \"Cosign verification accepts any valid Rekor entry under certain conditions\", \"source\": {\"advisory\": \"GHSA-whqx-f9j3-ch6m\", \"discovery\": \"UNKNOWN\"}, \"metrics\": [{\"cvssV3_1\": {\"scope\": \"UNCHANGED\", \"version\": \"3.1\", \"baseScore\": 5.5, \"attackVector\": \"LOCAL\", \"baseSeverity\": \"MEDIUM\", \"vectorString\": \"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N\", \"integrityImpact\": \"HIGH\", \"userInteraction\": \"NONE\", \"attackComplexity\": \"LOW\", \"availabilityImpact\": \"NONE\", \"privilegesRequired\": \"LOW\", \"confidentialityImpact\": \"NONE\"}}], \"affected\": [{\"vendor\": \"sigstore\", \"product\": \"cosign\", \"versions\": [{\"status\": \"affected\", \"version\": \"\u003c 3.0.4\"}, {\"status\": \"affected\", \"version\": \"\u003c 2.6.2\"}]}], \"references\": [{\"url\": \"https://github.com/sigstore/cosign/security/advisories/GHSA-whqx-f9j3-ch6m\", \"name\": \"https://github.com/sigstore/cosign/security/advisories/GHSA-whqx-f9j3-ch6m\", \"tags\": [\"x_refsource_CONFIRM\"]}, {\"url\": \"https://github.com/sigstore/cosign/pull/4623\", \"name\": \"https://github.com/sigstore/cosign/pull/4623\", \"tags\": [\"x_refsource_MISC\"]}, {\"url\": \"https://github.com/sigstore/cosign/commit/6832fba4928c1ad69400235bbc41212de5006176\", \"name\": \"https://github.com/sigstore/cosign/commit/6832fba4928c1ad69400235bbc41212de5006176\", \"tags\": [\"x_refsource_MISC\"]}], \"descriptions\": [{\"lang\": \"en\", \"value\": \"Cosign provides code signing and transparency for containers and binaries. Prior to versions 2.6.2 and 3.0.4, Cosign bundle can be crafted to successfully verify an artifact even if the embedded Rekor entry does not reference the artifact\u0027s digest, signature or public key. When verifying a Rekor entry, Cosign verifies the Rekor entry signature, and also compares the artifact\u0027s digest, the user\u0027s public key from either a Fulcio certificate or provided by the user, and the artifact signature to the Rekor entry contents. Without these comparisons, Cosign would accept any response from Rekor as valid. A malicious actor that has compromised a user\u0027s identity or signing key could construct a valid Cosign bundle by including any arbitrary Rekor entry, thus preventing the user from being able to audit the signing event. This issue has been patched in versions 2.6.2 and 3.0.4.\"}], \"problemTypes\": [{\"descriptions\": [{\"lang\": \"en\", \"type\": \"CWE\", \"cweId\": \"CWE-345\", \"description\": \"CWE-345: Insufficient Verification of Data Authenticity\"}]}], \"providerMetadata\": {\"orgId\": \"a0819718-46f1-4df5-94e2-005712e83aaa\", \"shortName\": \"GitHub_M\", \"dateUpdated\": \"2026-01-10T06:11:09.426Z\"}}}",
      "cveMetadata": "{\"cveId\": \"CVE-2026-22703\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2026-01-12T16:43:57.302Z\", \"dateReserved\": \"2026-01-08T19:23:09.857Z\", \"assignerOrgId\": \"a0819718-46f1-4df5-94e2-005712e83aaa\", \"datePublished\": \"2026-01-10T06:11:09.426Z\", \"assignerShortName\": \"GitHub_M\"}",
      "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.