Medium 5.8Published Oct 12, 2026

CVE-2026-104774OWASP Coraza WAF: jsDecode Off-by-One in Octal Escape Handling Enables WAF Bypass

Updated under an hour ago (2026-10-19 09:10 UTC)

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Exploited in the last 30 days

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.

CVSS: 5.8 MEDIUM (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N
Weakness (CWE): CWE-172, CWE-193, CWE-693
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: GitHub_M
NVD analysis: Deferred
Record last updated: Oct 13, 2026
First seen by InfoSec Signals: Oct 12, 2026

Affected products

Affected products

corazawaf coraza corazawaf:coraza (from the name)	from 3.0.0, < 3.8.0	CNA record

References

https://github.com/corazawaf/coraza/security/advisories/GHSA-pc5q-qfxp-ggqvx-refsource-confirm
https://github.com/corazawaf/coraza/commit/f9b7afdbcedce7ad814663eaee2e342578ea3bb2x-refsource-misc
https://github.com/corazawaf/coraza/releases/tag/v3.8.0x-refsource-misc

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.