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Fencer Intel
medium 5.8

CVE-2026-41508 json

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

published last mo. modified 20d ago also EUVD-2026-97828 , GHSA-r3rm-qphw-hh76 , GO-2026-6670

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
  • coraza coraza 3.8.0

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CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
27d ago

Exploit prediction

0.50% chance of exploitation in the next 30 days, higher than 42% of all scored CVEs (FIRST EPSS, 2026-11-09).

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

Weakness
  • CWE-693 Protection Mechanism Failure
  • CWE-755 Improper Handling of Exceptional Conditions
  • CWE-20 Improper Input Validation

References

Sources

Fencer Intel 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.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.