Vulnerability · Published Oct 12, 2026 · Assigned by GitHub_M
CVE-2026-41508OWASP Coraza WAF: Truncated multipart body bypasses MULTIPART_STRICT_ERROR (rule 200003) via silent io.ErrUnexpectedEOF handling
Medium 5.8
In plain English
A medium-severity security flaw in coraza from corazawaf. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 43% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official 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 packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Go | github.com/corazawaf/coraza | no fix listed | GO-2026-6670 |
| Go | github.com/corazawaf/coraza/v2 | no fix listed | GO-2026-6670 |
| Go | github.com/corazawaf/coraza/v3 | 3.8.0 | GHSA-r3rm-qphw-hh76 |
| Go | github.com/corazawaf/coraza/v3 | 3.8.0 | GO-2026-6670 |
Affected products (as reported)
Weakness: CWE-693, CWE-755 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N
References
- https://github.com/corazawaf/coraza/security/advisories/GHSA-r3rm-qphw-hh76 x_refsource_CONFIRM
- https://github.com/corazawaf/coraza/commit/f94c81bec209f658120c418448d0590a549b71df x_refsource_MISC
- https://github.com/corazawaf/coraza/releases/tag/v3.8.0 x_refsource_MISC