# CVE-2026-41508: Coraza: Truncated multipart body bypasses MULTIPART_STRICT_ERROR (rule 200003) via silent io.ErrUnexpectedEOF handling

> Remote attackers can bypass WAF multipart inspection rules by sending truncated bodies, allowing malicious payloads to reach backend servers.

- **Severity:** Medium 5.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 12 Oct 2026
- **Updated:** 13 Oct 2026
- **Also known as:** GHSA-r3rm-qphw-hh76, GO-2026-6670

## What is CVE-2026-41508?

CVE-2026-41508 is a medium-severity vulnerability in corazawaf coraza, published on 12 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### 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.

Weakness: CWE-755 (Improper Handling of Exceptional Conditions), CWE-693 (Protection Mechanism Failure)

## Which versions are affected by CVE-2026-41508?

5 open source packages ship an affected version, including github.com/corazawaf/coraza/v3, github.com/corazawaf/coraza and github.com/corazawaf/coraza/v2.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `github.com/corazawaf/coraza/v3` | Go | From 3.4.0 | 3.8.0 |
| `github.com/corazawaf/coraza/v3` | Go | From 3.4.0 | 3.8.0 |
| `github.com/corazawaf/coraza/v3` | Go | From 3.4.0 | 3.8.0 |
| `github.com/corazawaf/coraza` | Go | All versions | None |
| `github.com/corazawaf/coraza/v2` | Go | All versions | None |

## How do I fix CVE-2026-41508?

Upgrade github.com/corazawaf/coraza/v3 to 3.8.0 or later.

## Is CVE-2026-41508 being exploited?

There is no known exploitation of CVE-2026-41508 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-41508 and fix it if it is affected.

What it is: CVE-2026-41508 is a medium-severity vulnerability in corazawaf coraza, published on 12 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-41508 in the wild and no public exploit code.

Affected packages and fixed versions:
- github.com/corazawaf/coraza/v3 (Go): affected from 3.4.0; fixed in 3.8.0
- github.com/corazawaf/coraza/v3 (Go): affected from 3.4.0; fixed in 3.8.0
- github.com/corazawaf/coraza/v3 (Go): affected from 3.4.0; fixed in 3.8.0
- github.com/corazawaf/coraza (Go): affected all versions; no fix listed
- github.com/corazawaf/coraza/v2 (Go): affected all versions; no fix listed

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-41508/ (Markdown: https://insights.sbomify.com/CVE-2026-41508/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-41508
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-41508
- OSV: https://osv.dev/vulnerability/CVE-2026-41508

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-41508/
Summaries are generated and may contain mistakes; the official description above is the record.