CVE-2026-41508 json
OWASP Coraza WAF: Truncated multipart body bypasses MULTIPART_STRICT_ERROR (rule 200003) via silent io.ErrUnexpectedEOF handling
published 2026-10-06 33 d ago modified 2026-10-20 20 d ago also GHSA-r3rm-qphw-hh76 , GO-2026-6670 , EUVD-2026-97828
- cvss
- 5.8
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.5%
- EPSS 0.5% chance of exploitation in 30 days, percentile 42%
- public exploits
- 0
- none known
Summary
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.
Patch / fix
- go github.com/corazawaf/coraza/v3 3.8.0
CISA SSVC
- Exploitation
- none
- Automatable
- yes
- Technical impact
- partial
- Assessed
- 26 d ago
Exploit prediction
0.50% chance of exploitation in the next 30 days, higher than 42% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 5.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N |
| GitHub | 3.1 | 5.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| go | github.com/corazawaf/coraza/v3 | >=3.4.0, <3.8.0 |
3.8.0 |
| go | github.com/corazawaf/coraza | all versions |
no fix listed |
| go | github.com/corazawaf/coraza/v2 | all versions |
no fix listed |
Affected products
- corazawaf coraza
Classification
References
Sources
- CVE List CVE-2026-41508
- GitHub Advisory GHSA-r3rm-qphw-hh76
- NVD CVE-2026-41508
- OSV GO-2026-6670
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.