What’s Vulnerable › Vulnerabilities

CVE-2026-41508: OWASP Coraza WAF: Truncated multipart body bypasses MULTIPART_STRICT_ERROR (rule 200003) via silent io.ErrUnexpectedEOF handling

• Severity: medium (CVSS 5.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-10-12 · updated 2026-10-16
• Weakness: CWE-693

Description

OWASP Coraza WAF is a golang modsecurity compatible web application firewall library. From 3.4.0 until 3.8.0, the multipart processor in internal/bodyprocessors/multipart.go treats io.ErrUnexpectedEOF as nonfatal without setting MULTIPART_STRICT_ERROR. A remote attacker can submit a truncated multipart body that produces io.ErrUnexpectedEOF, causing parsing to stop without raising the strict-error signal used by the recommended defensive rule. Rules 200002 and 200003 do not fire, allowing multipart parser-disagreement payloads to reach a backend that interprets the truncated body differently. This issue is fixed in version 3.8.0.

Affected products

• corazawaf coraza: from 3.4.0, < 3.8.0

References

• https://github.com/corazawaf/coraza/commit/f94c81bec209f658120c418448d0590a549b71df
• https://github.com/corazawaf/coraza/releases/tag/v3.8.0
• https://github.com/corazawaf/coraza/security/advisories/GHSA-r3rm-qphw-hh76

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