# CVE-2026-41508: Coraza multipart strict validation bypass via truncated body

Source: https://junglewise.ai/threats/cve-2026-41508-coraza-truncated-multipart-body-bypasses-multipart-strict-error  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-12. Updated: 2026-10-06  
License: CC BY 4.0 with a link back

CVE-2026-41508 · Severity: medium · CVSS 5.8 · Published 2026-10-12

Coraza is a web application firewall that inspects HTTP requests to block malicious payloads. A flaw in how it handles incomplete multipart request bodies allows attackers to bypass a critical validation rule (MULTIPART_STRICT_ERROR) by crafting truncated requests, enabling parser-confusion attacks where Coraza and the backend application disagree on request structure. This can lead to payload smuggling and WAF evasion.

Technologies: [github.com/corazawaf/coraza (Go)](https://junglewise.ai/threats/technologies/github-com-corazawaf-coraza), [github.com/corazawaf/coraza/v2 (Go)](https://junglewise.ai/threats/technologies/github-com-corazawaf-coraza-v2), [github.com/corazawaf/coraza/v3 (Go)](https://junglewise.ai/threats/technologies/github-com-corazawaf-coraza-v3). Vendors: [Go](https://junglewise.ai/threats/vendors/go).

## Quick answers

**Is CVE-2026-41508 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-41508 being exploited in the wild.

**How severe is CVE-2026-41508?** Medium severity, with a CVSS score of 5.8, published 12 October 2026.

**Which products and versions are affected?** Coraza Project Coraza 3.4.0 through 3.7.0; github.com/corazawaf/coraza (Go) SEMVER:introduced=0; github.com/corazawaf/coraza/v2 (Go) SEMVER:introduced=0; github.com/corazawaf/coraza/v3 (Go) >= 3.4.0, <= 3.7.0, SEMVER:introduced=3.4.0,fixed=3.8.0.

**Is there a fix for CVE-2026-41508?** Yes. github.com/corazawaf/coraza/v3 (Go): upgrade to 3.8.0 or later. Until then: Apply a two-line code change at three sites in internal/bodyprocessors/multipart.go to set MULTIPART_STRICT_ERROR when io.ErrUnexpectedEOF is encountered, restoring the strict validation flag. Operators using ProcessPartial mode should pair this with config-level changes such as downgrading rule 200003 to detection-only or adding secondary checks on SecRequestBodyLimit.</anigation>
<parameter name="timeline">[{"kind":"other","at":"2026-03-06","note":"Vulnerable code introduced in PR #1453, merged"},{"kind":"disclosed","at":"2026-10-06","note":"Advisory published (GHSA-r3rm-qphw-hh76)"}] Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-41508 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-41508?** Check whether you run Coraza Project Coraza, github.com/corazawaf/coraza (Go), github.com/corazawaf/coraza/v2 (Go) or one of the others listed at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- github.com/corazawaf/coraza/v3 (Go): upgrade to 3.8.0 or later

  ```sh
  go get github.com/corazawaf/coraza/v3@v3.8.0
  ```


Apply a two-line code change at three sites in internal/bodyprocessors/multipart.go to set MULTIPART_STRICT_ERROR when io.ErrUnexpectedEOF is encountered, restoring the strict validation flag. Operators using ProcessPartial mode should pair this with config-level changes such as downgrading rule 200003 to detection-only or adding secondary checks on SecRequestBodyLimit.</anigation>
<parameter name="timeline">[{"kind":"other","at":"2026-03-06","note":"Vulnerable code introduced in PR #1453, merged"},{"kind":"disclosed","at":"2026-10-06","note":"Advisory published (GHSA-r3rm-qphw-hh76)"}]

## Technical details

The multipart body processor in Coraza's internal/bodyprocessors/multipart.go silently swallows io.ErrUnexpectedEOF errors (since v3.4.0) without setting the MULTIPART_STRICT_ERROR flag, allowing malformed or truncated multipart bodies to pass validation. An attacker exploits this by truncating a multipart body (e.g., omitting the closing boundary or cutting off mid-field) to bypass rule 200003, the sole defense-in-depth check for multipart parser inconsistencies. The fix requires setting MULTIPART_STRICT_ERROR when encountering io.ErrUnexpectedEOF at three code sites.

## Affected products

- Coraza Project Coraza 3.4.0 through 3.7.0

## Identifiers

- CVE-2026-41508
- GHSA-r3rm-qphw-hh76
- GO-2026-6670

## Related threats

- [Coraza multipart filename rule bypass via RFC 5987 charset handling](https://junglewise.ai/threats/cve-2026-114101-coraza-before-3-8-1-extracts-multipart-upload-filenames-with-go)
- [Coraza request body inspection bypass in Content-Type parsing](https://junglewise.ai/threats/cve-2026-114100-coraza-from-3-0-4-before-3-8-1-contains-a-request-body)
- [Coraza JSON body processor key collision WAF bypass](https://junglewise.ai/threats/cve-2026-114099-coraza-from-3-0-0-before-3-8-1-has-a-json-body-processor-that)
- [Coraza CRLF injection in Native audit-log format](https://junglewise.ai/threats/cve-2026-41504-coraza-native-audit-log-format-allows-crlf-injection-and-log)
- [Coraza WAF argument limit bypass via parameter flooding](https://junglewise.ai/threats/cve-2026-41510-coraza-silent-argument-drop-at-argumentlimit-allows-bypass-of)