Bug 2558782

Summary: CVE-2026-115207 patch: Filename validation bypass in reversal fallback allows file creation outside the working directory [fedora-all]
Product: [Fedora] Fedora Reporter: Vladimir Vasilev <vvasilev>
Component: patchAssignee: Tim Waugh <twaugh>
Status: NEW --- QA Contact: Fedora Extras Quality Assurance <extras-qa>
Severity: medium Docs Contact:
Priority: medium    
Version: rawhideCC: luk.claes, twaugh
Target Milestone: ---Keywords: Security, SecurityTracking
Target Release: ---   
Hardware: Unspecified   
OS: Unspecified   
Whiteboard: {"flaws": ["476d7acb-c7f7-4552-89a3-6521bc52b390"]}
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
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Bug Depends On:    
Bug Blocks: 2558775    

Description Vladimir Vasilev 2026-10-22 08:03:08 UTC 
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.

A flaw was found in GNU patch. The reversal fallback in intuit_diff_type() in src/pch.c selects a filename from the patch headers without applying the name_is_valid() check that normally rejects absolute paths. A crafted unified diff that appears to delete a nonexistent file, with an absolute filename in both headers and an epoch timestamp for the new file, can trigger automatic reversal when applied with patch -p0 -t. The unvalidated absolute filename reaches the filesystem operations, allowing attacker-controlled file creation outside the working directory with the permissions of the account running patch. Exploitation requires a user or workflow to apply the crafted patch; it does not bypass operating-system filesystem permissions.