CVE-2026-86463 Apache CXF: FIQL Query Parser Denial of Service

High 7.5 Published 9 Oct 2026 Updated 15 Oct 2026

An attacker can cause excessive CPU consumption in Apache CXF by sending crafted FIQL queries, leading to service disruption.

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Over the internet
Victim action needed: Not needed
Fix: Available

What is CVE-2026-86463?

CVE-2026-86463 is a high-severity denial of service vulnerability in Apache Cxf, published on 9 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

Apache CXF's FIQL query parser has a vulnerability in how it searches for operators in query expressions. The search pattern can get stuck trying many combinations when it encounters a long string without an operator, causing the parser to consume excessive CPU time. An attacker can send a crafted query to make the server use up CPU resources, potentially slowing down or stopping other requests. The fix was to limit FIQL expressions to 4 KiB by default, preventing attackers from sending extremely long inputs while still allowing normal queries.

Users are recommended to upgrade to versions 4.2.4 or 4.1.9 or 3.6.13, which fix this issue.

Weakness: CWE-400

Which versions are affected by CVE-2026-86463?

It affects 1 product.

Products include Apache Cxf.

How do I fix CVE-2026-86463?

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-2026-86463 being exploited?

There is no known exploitation of CVE-2026-86463 in the wild and no public exploit code.

All Apache Cxf vulnerabilities

Sources

Also known as CLEANSTART-2026-XT41659, GHSA-ppm6-prq5-wv37.