OWASP Coraza WAF: jsDecode Off-by-One in Octal Escape Handling Enables WAF Bypass
- Published
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Not listed in CISA KEV
- Fix
- Fixed in 3.8.0
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
- Exploitation: poc
- Automatable: yes
- Technical impact: partial
Summary
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.
Timeline
- CVE published
- CISA SSVC assessment
Exploitation: poc · Automatable: yes · Technical impact: partial
- Record last updated
Affected versions
- corazawaf coraza
From 3.0.0 · fixed in 3.8.0
- github.com/corazawaf/coraza/v3Go
From 3.0.0 · fixed in 3.8.0
- github.com/corazawaf/corazaGo
All versions
- github.com/corazawaf/coraza/v2Go
All versions