Description
OWASP 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.
Published: 2026-10-12
Score: 5.8 Medium
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
AI Analysis

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Remediation

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Tracking

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Advisories
Source ID Title
Github GHSA Github GHSA GHSA-pc5q-qfxp-ggqv Coraza: jsDecode Off-by-One in Octal Escape Handling Enables WAF Bypass
History

Mon, 12 Oct 2026 20:00:00 +0000

Type Values Removed Values Added
Description OWASP 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.
Title OWASP Coraza WAF: jsDecode Off-by-One in Octal Escape Handling Enables WAF Bypass
Weaknesses CWE-172
CWE-193
CWE-693
References
Metrics cvssV3_1

{'score': 5.8, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N'}


Subscriptions

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-10-12T19:58:39.383Z

Reserved: 2026-10-02T13:06:26.764Z

Link: CVE-2026-104774

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-10-12T20:17:07.617

Modified: 2026-10-12T20:17:07.617

Link: CVE-2026-104774

cve-icon Redhat

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cve-icon OpenCVE Enrichment

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Weaknesses