CVE-2026-107835 OWASP Coraza WAF: Cookie Parser Confusion
An attacker can bypass WAF rules by crafting cookie headers that are parsed differently by Coraza and the backend application.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-107835?
CVE-2026-107835 is a medium-severity vulnerability in corazawaf coraza, published on 9 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Weakness: CWE-436
Which versions are affected by CVE-2026-107835?
5 open source packages ship an affected version, including github.com/corazawaf/coraza/v3, github.com/corazawaf/coraza and github.com/corazawaf/coraza/v2.
| Package | Affected | Fixed in |
|---|---|---|
github.com/corazawaf/coraza/v3 Go | All versions | 3.8.1 |
github.com/corazawaf/coraza/v3 Go | All versions | 3.8.1 |
github.com/corazawaf/coraza/v3 Go | All versions | 3.8.1 |
github.com/corazawaf/coraza Go | All versions | None |
github.com/corazawaf/coraza/v2 Go | All versions | None |
How do I fix CVE-2026-107835?
Upgrade github.com/corazawaf/coraza/v3 to 3.8.1 or later.
Is CVE-2026-107835 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-107835 exists.
Sources
Also known as GHSA-g4qm-m288-5cp9, GO-2026-6694.