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Medium · 5.8 CVE-2026-41508 EUVD-2026-97828GHSA-r3rm-qphw-hh76GO-2026-6670

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

Published Oct 12, 2026 · Updated Oct 13, 2026 · Assigned by GitHub_M

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

VendorProductAffectedFixed
corazawaf coraza >= 3.4.0, < 3.8.0 —

Affected packages

EcosystemPackageAffectedFixedRecord
Go github.com/corazawaf/coraza all versions — GO-2026-6670
Go github.com/corazawaf/coraza/v2 all versions — GO-2026-6670
Go github.com/corazawaf/coraza/v3 >= 3.4.0, < 3.8.0 3.8.0 GHSA-r3rm-qphw-hh76

References