Apache CXF FIQL Parser DoS via Long Query (4KiB limit)
CVE-2026-86463 Published on October 9, 2026
Apache CXF: FIQL Query Parser Denial of Service
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.
Vulnerability Analysis
CVE-2026-86463 can be exploited with network access, and does not require authorization privileges or user interaction. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality and integrity, and a high impact on availability.
Weakness Type
What is a Resource Exhaustion Vulnerability?
The software does not properly control the allocation and maintenance of a limited resource, thereby enabling an actor to influence the amount of resources consumed, eventually leading to the exhaustion of available resources.
CVE-2026-86463 has been classified to as a Resource Exhaustion vulnerability or weakness.
Products Associated with CVE-2026-86463
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Affected Versions
Apache Software Foundation Apache CXF:- Version 4.2.0 and below 4.2.4 is affected.
- Version 4.0.0 and below 4.1.9 is affected.
- Before 3.6.13 is affected.