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CVE-2026-42563

HIGH Exploitation: PoC
7.7
CVSS 4.0
Description
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.

Metadata

CVE ID
CVE-2026-42563
State
PUBLISHED
Assigner
GitHub_M
Reserved
2026-04-28 17:26 UTC
Published
2026-06-10 21:47 UTC
Last updated
2026-06-12 03:55 UTC
Primary CWE
CWE-78
CWE-78: Improper Neutralization of Special Elements used in …
Vendor / Product
jelmer / dulwich
Sources
cve.org  ·  NVD

Severity & Metrics

7.7 HIGH CVSS 4.0
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 — CISA Coordinator
Exploitation
PoC
Automatable
no
Tech. Impact
total
Affected products (1)
VendorProductPlatformVersions
jelmer dulwich — >= 0.24.0, < 1.2.5
Weakness (CWE)
CWESourceDescription
CWE-78 cna CWE-78: Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')
CVSS scores (1)
ScoreSeverityVersionSourceVector
7.7 HIGH 4.0 cna 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
References (3)
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