CVE-2026-41508

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

Published Oct 12, 2026 CVSS 3.1 · 5.8 Medium EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Github GHSA Github GHSA GHSA-r3rm-qphw-hh76 Coraza: Truncated multipart body bypasses MULTIPART_STRICT_ERROR (rule 200003) via silent io.ErrUnexpectedEOF handling
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Coraza
Coraza coraza
Vendors & Products Coraza
Coraza coraza
Type Values Removed Values Added
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.
Title OWASP Coraza WAF: Truncated multipart body bypasses MULTIPART_STRICT_ERROR (rule 200003) via silent io.ErrUnexpectedEOF handling
Weaknesses CWE-693
CWE-755
References
Metrics cvssV3_1

{'score': 5.8, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
Oct 13, 2026, 8:24 PM
Reserved
Apr 20, 2026, 6:18 PM
Status
Deferred
Published
Oct 12, 2026, 9:17 PM
Modified
Oct 16, 2026, 8:04 PM