CVE-2026-41508 · GHSA-r3rm-qphw-hh76

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

Risk score: 53/100
CVSS: 5.8 v3.1
Exploit chance (30 days): 0.5%
Published: 6 Oct 2026

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What to know

What it is: 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 produ…
Affected: github.com/corazawaf/coraza/v3 (go) >= 3.4.0, <= 3.7.0
Fix: Upgrade github.com/corazawaf/coraza/v3 to 3.8.0 or later.
Exploitation: Public proof of concept

Why it is Yellow

CVSS 5.8 medium
Public exploit or proof of concept referenced
On your watchlist: Go

Affected packages

Package	Ecosystem	Vulnerable	Fixed in
github.com/corazawaf/coraza/v3	go	>= 3.4.0, <= 3.7.0	3.8.0

References

Original 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.

Last activity 6 Oct 2026. Patch Forecast updates every hour.