Vulnerability-Lookup

GHSA-H3G3-4265-WV56

Vulnerability from github – Published: 2026-08-05 21:31 – Updated: 2026-08-05 21:31

Details

A path traversal vulnerability was identified in GitHub Enterprise Server that allowed an unauthenticated attacker to delete arbitrary files and directories on the instance, including the entire user storage directory containing Git LFS objects, release assets, attachments, and avatars. The X-GitHub-Request-Id request header was used without sanitization as a filesystem path segment for the upload buffer directory, so a traversal value pointed the buffer at an arbitrary path and the deferred cleanup routine recursively removed the traversed target. Exploitation required only network reachability to the instance and no authentication, and it worked even when private mode was enabled. This vulnerability affected all versions of GitHub Enterprise Server prior to 3.22 and was fixed in versions 3.21.4, 3.20.6, 3.19.10, 3.18.13 and 3.17.19. This vulnerability was reported via the GitHub Bug Bounty program.

Severity

8.8 (High)


                  
                    CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N

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{
  "affected": [],
  "aliases": [
    "CVE-2026-17556"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-22"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-08-05T20:17:06Z",
    "severity": "HIGH"
  },
  "details": "A path traversal vulnerability was identified in GitHub Enterprise Server that allowed an unauthenticated attacker to delete arbitrary files and directories on the instance, including the entire user storage directory containing Git LFS objects, release assets, attachments, and avatars. The X-GitHub-Request-Id request header was used without sanitization as a filesystem path segment for the upload buffer directory, so a traversal value pointed the buffer at an arbitrary path and the deferred cleanup routine recursively removed the traversed target. Exploitation required only network reachability to the instance and no authentication, and it worked even when private mode was enabled. This vulnerability affected all versions of GitHub Enterprise Server prior to 3.22 and was fixed in versions 3.21.4, 3.20.6, 3.19.10, 3.18.13 and 3.17.19. This vulnerability was reported via the GitHub Bug Bounty program.",
  "id": "GHSA-h3g3-4265-wv56",
  "modified": "2026-08-05T21:31:38Z",
  "published": "2026-08-05T21:31:38Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-17556"
    },
    {
      "type": "WEB",
      "url": "https://docs.github.com/en/enterprise-server@3.17/admin/release-notes#3.17.19"
    },
    {
      "type": "WEB",
      "url": "https://docs.github.com/en/enterprise-server@3.18/admin/release-notes#3.18.13"
    },
    {
      "type": "WEB",
      "url": "https://docs.github.com/en/enterprise-server@3.19/admin/release-notes#3.19.10"
    },
    {
      "type": "WEB",
      "url": "https://docs.github.com/en/enterprise-server@3.20/admin/release-notes#3.20.6"
    },
    {
      "type": "WEB",
      "url": "https://docs.github.com/en/enterprise-server@3.21/admin/release-notes#3.21.4"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
      "type": "CVSS_V4"
    }
  ]
}

CVE-2026-17556 (GCVE-0-2026-17556)

Vulnerability from cvelistv5 – Published: 2026-08-05 20:05 – Updated: 2026-08-06 13:11

Title

Path traversal in GitHub Enterprise Server allowed unauthenticated deletion of instance storage via the X-GitHub-Request-Id header

Summary

Severity

8.8 (High)


                        
                          CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N

SSVC

Exploitation: none Automatable: yes Technical Impact: partial

CISA Coordinator (v2.0.3)

CWE

CWE-22 - Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

Assigner

GitHub_P

References

5 references

URL	Tags
https://docs.github.com/en/enterprise-server@3.17…	release-notes
https://docs.github.com/en/enterprise-server@3.18…	release-notes
https://docs.github.com/en/enterprise-server@3.19…	release-notes
https://docs.github.com/en/enterprise-server@3.20…	release-notes
https://docs.github.com/en/enterprise-server@3.21…	release-notes

Impacted products

1 product

Vendor	Product	Version
GitHub	Enterprise Server	Affected: 3.17.0 , ≤ 3.17.18 (semver) Affected: 3.18.0 , ≤ 3.18.12 (semver) Affected: 3.19.0 , ≤ 3.19.9 (semver) Affected: 3.20.0 , ≤ 3.20.5 (semver) Affected: 3.21.0 , ≤ 3.21.3 (semver)

Credits

r31n

Show details on NVD website

JSON

To clipboard

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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.

Action not permitted

GHSA-H3G3-4265-WV56

CVE-2026-17556 (GCVE-0-2026-17556)

Tags

Sightings

Nomenclature