CVE-2019-25043 Denial of service in n/a
A malformed Cookie header causes a worker-process crash in ModSecurity, leading to denial of service for web servers using this WAF.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2019-25043?
CVE-2019-25043 is a medium-severity denial of service vulnerability in n/a, published on 6 May 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
ModSecurity 3.x before 3.0.4 mishandles key-value pair parsing, as demonstrated by a "string index out of range" error and worker-process crash for a "Cookie: =abc" header.
Weakness: CWE-755
Which versions are affected by CVE-2019-25043?
It affects 1 product.
Products include Owasp Modsecurity.
How do I fix CVE-2019-25043?
Upgrade to a fixed version.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2019-25043 being exploited?
There is no known exploitation of CVE-2019-25043 in the wild and no public exploit code.
Other vulnerabilities in n/a
- CVE-2026-52747 Security feature bypass in ModSecurity
- CVE-2024-1019 WAF bypass of the ModSecurity v3 release line
- CVE-2026-42268 ModSecurity: Unsigned integer underflow in @verifySSN / @verifyCPF / @verifySVNR operators
- CVE-2026-30923 libModSecurity3 denial of service via segfault when using t:hexDecode on single-character query strings
- CVE-2025-48866 ModSecurity has possible DoS vulnerability in sanitiseArg action
Sources
Also known as DEBIAN-CVE-2019-25043, GHSA-p89w-8r2h-7mjp, UBUNTU-CVE-2019-25043.