Vulnerability-Lookup

UBUNTU-CVE-2026-44309 (CVE-2026-44309)

Vulnerability from osv_ubuntu – Published: 2026-05-15 17:16 – Updated: 2026-07-02 16:14 – Source website

Details

Gitsign is a keyless Sigstore to signing tool for Git commits with your a GitHub / OIDC identity. Prior to 0.16.0, gitsign verify and gitsign verify-tag re-encode commit/tag objects through go-git's EncodeWithoutSignature before checking the signature, instead of verifying against the raw git object bytes. For malformed objects with duplicate tree headers, git-core and go-git parse different trees: git-core uses the first, go-git uses the second. A signature crafted over the go-git-normalized form (second tree) passes gitsign verify while git-core resolves the commit to a completely different tree. This breaks the invariant that a verified signature, the commit semantics git-core presents to users, and the object hash logged in Rekor all refer to the same content. This vulnerability is fixed in 0.16.0.

Severity

5.3 (Medium)


                    
                      CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:H/A:N

N/A (UNKNOWN)


                    
                      medium

References

URL

Type

	https://ubuntu.com/security/CVE-2026-44309	REPORT
	https://www.cve.org/CVERecord?id=CVE-2026-44309	REPORT
	https://github.com/sigstore/gitsign/security/advi…	REPORT

JSON

To clipboard

{
  "affected": [
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "gitsign",
            "binary_version": "0.13.0-2"
          },
          {
            "binary_name": "golang-github-sigstore-gitsign-dev",
            "binary_version": "0.13.0-2"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:25.10",
        "name": "gitsign",
        "purl": "pkg:deb/ubuntu/gitsign@0.13.0-2?arch=source\u0026distro=questing"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "0.12.0-4",
        "0.13.0-1",
        "0.13.0-2"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "gitsign",
            "binary_version": "0.13.0-4ubuntu0.26.04.1~esm1"
          },
          {
            "binary_name": "golang-github-sigstore-gitsign-dev",
            "binary_version": "0.13.0-4ubuntu0.26.04.1~esm1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:26.04:LTS",
        "name": "gitsign",
        "purl": "pkg:deb/ubuntu/gitsign@0.13.0-4ubuntu0.26.04.1~esm1?arch=source\u0026distro=esm-apps/resolute"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "0.13.0-2",
        "0.13.0-3",
        "0.13.0-4",
        "0.13.0-4ubuntu0.26.04.1~esm1"
      ]
    }
  ],
  "aliases": [],
  "details": "Gitsign is a keyless Sigstore to signing tool for Git commits with your a GitHub / OIDC identity. Prior to 0.16.0, gitsign verify and gitsign verify-tag re-encode commit/tag objects through go-git\u0027s EncodeWithoutSignature before checking the signature, instead of verifying against the raw git object bytes. For malformed objects with duplicate tree headers, git-core and go-git parse different trees: git-core uses the first, go-git uses the second. A signature crafted over the go-git-normalized form (second tree) passes gitsign verify while git-core resolves the commit to a completely different tree. This breaks the invariant that a verified signature, the commit semantics git-core presents to users, and the object hash logged in Rekor all refer to the same content. This vulnerability is fixed in 0.16.0.",
  "id": "UBUNTU-CVE-2026-44309",
  "modified": "2026-07-02T16:14:45Z",
  "published": "2026-05-15T17:16:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-44309"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-44309"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/sigstore/gitsign/security/advisories/GHSA-7rmh-48mx-2vwc"
    }
  ],
  "related": [],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:H/A:N",
      "type": "CVSS_V3"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2026-44309"
  ]
}

CVE-2026-44309 (GCVE-0-2026-44309)

Vulnerability from cvelistv5 – Published: 2026-05-15 16:22 – Updated: 2026-05-15 17:43

Title

gitsign verify accepts signatures over go-git-normalized bytes, enabling trust confusion on malformed commits

Summary

Severity

5.3 (Medium)


                        
                          CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:H/A:N

SSVC

Exploitation: poc Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-05-15 17:43 UTC

CWE

CWE-347 - Improper Verification of Cryptographic Signature
CWE-295 - Improper Certificate Validation

Assigner

GitHub_M mitre root

References

1 reference

URL	Tags
https://github.com/sigstore/gitsign/security/advi…	x_refsource_CONFIRM

Impacted products

1 product

Vendor	Product	Version
sigstore	gitsign	Affected: < 0.16.0

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-44309",
                "options": [
                  {
                    "Exploitation": "poc"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-05-15T17:43:27.049597Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-05-15T17:43:59.446Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "references": [
          {
            "tags": [
              "exploit"
            ],
            "url": "https://github.com/sigstore/gitsign/security/advisories/GHSA-7rmh-48mx-2vwc"
          }
        ],
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "gitsign",
          "vendor": "sigstore",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 0.16.0"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "Gitsign is a keyless Sigstore to signing tool for Git commits with your a GitHub / OIDC identity. Prior to 0.16.0, gitsign verify and gitsign verify-tag re-encode commit/tag objects through go-git\u0027s EncodeWithoutSignature before checking the signature, instead of verifying against the raw git object bytes. For malformed objects with duplicate tree headers, git-core and go-git parse different trees: git-core uses the first, go-git uses the second. A signature crafted over the go-git-normalized form (second tree) passes gitsign verify while git-core resolves the commit to a completely different tree. This breaks the invariant that a verified signature, the commit semantics git-core presents to users, and the object hash logged in Rekor all refer to the same content. This vulnerability is fixed in 0.16.0."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "HIGH",
            "attackVector": "NETWORK",
            "availabilityImpact": "NONE",
            "baseScore": 5.3,
            "baseSeverity": "MEDIUM",
            "confidentialityImpact": "NONE",
            "integrityImpact": "HIGH",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "REQUIRED",
            "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:H/A:N",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-347",
              "description": "CWE-347: Improper Verification of Cryptographic Signature",
              "lang": "en",
              "type": "CWE"
            }
          ]
        },
        {
          "descriptions": [
            {
              "cweId": "CWE-295",
              "description": "CWE-295: Improper Certificate Validation",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-05-15T16:22:51.260Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/sigstore/gitsign/security/advisories/GHSA-7rmh-48mx-2vwc",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/sigstore/gitsign/security/advisories/GHSA-7rmh-48mx-2vwc"
        }
      ],
      "source": {
        "advisory": "GHSA-7rmh-48mx-2vwc",
        "discovery": "UNKNOWN"
      },
      "title": "gitsign verify accepts signatures over go-git-normalized bytes, enabling trust confusion on malformed commits"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-44309",
    "datePublished": "2026-05-15T16:22:51.260Z",
    "dateReserved": "2026-05-05T19:00:06.021Z",
    "dateUpdated": "2026-05-15T17:43:59.446Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

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.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.