OWASP Coraza WAF: jsDecode Off-by-One in Octal Escape Handling Enables WAF Bypass

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-104774
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-10-12 20:17:07 UTC
Updated2026-10-12 20:17:07 UTC
DescriptionOWASP Coraza WAF is a golang modsecurity compatible web application firewall library. From 3.0.0 until 3.8.0, the t:jsDecode transformation in internal/transformations/js_decode.go:64-70 includes the backslash in the octal buffer, causing ParseInt to fail and return a null byte. The flaw is triggered when a rule relies on t:jsDecode and the request contains JavaScript octal escape sequences. An unauthenticated attacker can encode attack syntax with JavaScript octal escapes so the backend decodes the intended bytes while Coraza rules using t:jsDecode inspect corrupted null-byte output. The mismatch can bypass WAF rules and expose the protected application to attacks such as cross-site scripting or SQL injection. This issue is fixed in version 3.8.0.

Risk And Classification

Primary CVSS: v3.1 5.8 MEDIUM from [email protected]

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N

Problem Types: CWE-172 | CWE-193 | CWE-693 | CWE-172 CWE-172: Encoding Error | CWE-193 CWE-193: Off-by-one Error | CWE-693 CWE-693: Protection Mechanism Failure

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary5.8MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N
3.1CNADECLARED5.8MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Changed
Confidentiality
None
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Corazawaf Coraza affected >= 3.0.0, < 3.8.0 Not specified

References

ReferenceSourceLinkTags
github.com/corazawaf/coraza/releases/tag/v3.8.0 [email protected] github.com
github.com/corazawaf/coraza/commit/f9b7afdbcedce7ad814663eaee2e342578ea3bb2 [email protected] github.com
github.com/corazawaf/coraza/security/advisories/GHSA-pc5q-qfxp-ggqv [email protected] github.com
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