CVE-2026-8159

Summary

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.

Affected Software

Weaknesses

• CWE-1333: CWE-1333: Inefficient Regular Expression Complexity

ADP Enrichment

CISA ADP Vulnrichment

• SSVC:
• Exploitation: none
  • Automatable: yes
  • Technical Impact: partial

References

• https://github.com/pillarjs/multiparty/security/advisories/GHSA-65x3-rw7q-gx94
• https://owasp.org/www-community/attacks/Regular_expression_Denial_of_Service_-_ReDoS
• https://cna.openjsf.org/security-advisories.html

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