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Fencer Vulns
high 7.7

CVE-2026-42563 json

Dulwich Vulnerable to Command Injection via Merge Driver Path

published 2026-05-28 5 mo ago modified 2026-09-10 1 mo ago also GHSA-9277-mp7x-85jf , PYSEC-2026-2464 , EUVD-2026-36175

cvss
7.7
version 4.0, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.6%
EPSS 0.6% chance of exploitation in 30 days, percentile 46%
public exploits
0
none known

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.

Patch / fix

  • pypi dulwich 1.2.5
  • dulwich Debian 14 1.2.5-1

debian advisories DEBIAN-CVE-2026-42563

  • python-dulwich openSUSE Tumbleweed 1.2.5-1.1

opensuse advisories openSUSE-SU-2026:10900-1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-42563 updated cvss 8.0

dulwich: Dulwich: Arbitrary code execution via malicious Git file paths during merge

  • Red Hat Ansible Automation Platform 2 ansible-automation-platform-26/controller-rhel9, ansible-automation-platform-27/controller-rhel9 Red Hat OpenShift AI (RHOAI) rhoai/odh-kserve-storage-initializer-rhel9
    affected: workaround, no fix available
  • Red Hat Ansible Automation Platform 2 ansible-automation-platform-26/eda-controller-rhel9, ansible-automation-platform-27/eda-controller-rhel9, ansible-automation-platform-26/lightspeed-chatbot-rhel9 Red Hat Enterprise Linux 7 resource-agents, resource-agents-gcp, resource-agents-sap, sap-cluster-connector, resource-agents-aliyun, resource-agents-sap-hana, +1 more Red Hat Enterprise Linux 8 resource-agents, resource-agents-gcp, resource-agents-paf, resource-agents-aliyun Red Hat OpenShift AI (RHOAI) rhoai/odh-kserve-agent-rhel9, rhoai/odh-kserve-router-rhel9, rhoai/odh-kserve-controller-rhel9, rhoai/odh-kserve-autogluon-server-rhel9
    not affected: vulnerable code not present
  • Red Hat OpenShift Container Platform 4 python-dulwich
    not affected: vulnerable code not in execute path
  • Red Hat Satellite 6 python-dulwich
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
total
Assessed
4 mo ago

Exploit prediction

0.56% chance of exploitation in the next 30 days, higher than 46% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/jelmer/dulwich/security/advisories/GHSA-9277-mp7x-85jf referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 4.0 7.7 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
CNA 4.0 7.7 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/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

Affected packages

ecosystem package affected fixed in
pypi dulwich
>=0.24.0, <1.2.5
1.2.5

Affected products

  • jelmer dulwich

Classification

Weakness
  • CWE-78 Improper Neutralization of Special Elements used in an OS Command

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.