{"id":"CVE-2026-8159","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-8159","generatedAt":"2026-10-28T07:04:17.075Z","title":"multiparty@4.2.3 and lower versions are vulnerable to denial of service via regular expression backtracking in the Content-Disposition filename parameter parser.","description":"multiparty@4.2.3 and lower versions are vulnerable to denial of service via regular expression backtracking in the Content-Disposition filename parameter parser. A crafted multipart upload with a long header value can cause regex matching to take seconds, blocking the event loop. Impact: any service accepting multipart uploads via multiparty is affected. Workarounds: limiting upload sizes at the proxy or gateway layer reduces but does not eliminate the attack surface, since a small header of around 8 KB is sufficient to trigger the vulnerable backtracking. Upgrade to multiparty@4.3.0 or higher.","published":"2026-05-12T10:16:49.000Z","lastModified":"2026-06-17T11:03:34.000Z","status":"Analyzed","sourceIdentifier":"ce714d77-add3-4f53-aff5-83d477b104bb","cvss":{"version":"3.1","score":7.5,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"},"cwe":["CWE-1333"],"affected":["pillarjs/multiparty"],"epss":{"score":0.00335,"percentile":0.26672,"date":"2026-10-27","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"high","text":"High impact if exploited, but EPSS currently rates exploitation as unlikely (0.34%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit."},"changes":[],"references":[{"url":"https://cna.openjsf.org/security-advisories.html","tags":["Third Party Advisory"],"source":"ce714d77-add3-4f53-aff5-83d477b104bb"},{"url":"https://github.com/pillarjs/multiparty/security/advisories/GHSA-65x3-rw7q-gx94","tags":["Mitigation","Vendor Advisory"],"source":"ce714d77-add3-4f53-aff5-83d477b104bb"},{"url":"https://owasp.org/www-community/attacks/Regular_expression_Denial_of_Service_-_ReDoS","tags":["Not Applicable"],"source":"ce714d77-add3-4f53-aff5-83d477b104bb"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-8159","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}