Executive brief
a2ui is a web framework component library used to build agent-driven web applications. A vulnerability in the updateComponents function allows remote attackers to cause excessive memory and CPU consumption by sending specially crafted requests, potentially degrading application performance and availability without requiring authentication.
Technical details
The vulnerability is an uncontrolled resource consumption flaw (CWE-400) in the updateComponents function of basic_functions.ts in the @a2ui/web_core module. The root cause involves three issues: component arrays lack maximum size validation despite minimum validation, Intl.NumberFormat instances are cached indefinitely based on untrusted agent-supplied parameters without eviction, and descendant notifications incur quadratic complexity in bound paths. An unauthenticated remote attacker can exploit this by sending maliciously large component arrays or many unique formatter configurations to gradually exhaust memory and degrade CPU performance over a session lifetime. The vendor was informed early but has not yet provided a patch; remediation requires implementing caps on components, using an LRU cache for formatters, and optimizing notification indexing.
Affected products
- a2ui-project a2ui 0.9, 0.9.1
Timeline
- 2026-09-16: disclosed