CVE-2026-107835: OWASP Coraza WAF: Cookie Parser Confusion

Severity: medium (CVSS 4.0 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-10-09 · updated 2026-10-16
Weakness: CWE-436

Description

OWASP Coraza WAF is a golang modsecurity compatible web application firewall library. Prior to 3.8.1, internal/cookies.ParseCookies in internal/cookies/cookies.go handles boundary ASCII control characters and control-only or empty cookie names differently from several backend cookie parsers. An unauthenticated attacker can craft a Cookie header so Coraza indexes or drops a cookie under a different name or value from the backend application, causing rules targeting REQUEST_COOKIES or REQUEST_COOKIES_NAMES to miss application-visible attacker data. Exploitation depends on the backend parser and affected rule scope, and interior control characters with inconsistent backend behavior are outside this advisory's remediation. This issue is fixed in version 3.8.1.

Affected products

Go Github.Com/Corazawaf/Coraza/V3: before 3.8.1 — fixed in 3.8.1
corazawaf coraza: before 3.8.1

How to fix

Upgrade to a fixed version: Go Github.Com/Corazawaf/Coraza/V3 3.8.1. Check the vendor advisory for mitigations.

References

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