The vulnerability is a cross‑site scripting flaw in the markdown rendering service of the a2ui a2a‑chat‑canvas component. An attacker can supply crafted markdown that bypasses the sanitizer, causing client browsers to execute injected JavaScript. The flaw corresponds to CWE‑79 and is listed under CWE‑94, indicating a code‑or‑command‑injection weakness in the rendering path. This can lead to session hijacking, data theft, defacement, or other client‑side compromises when the vulnerable component is rendered for a user.

Based on the description, it is inferred that any deployment that includes the a2a‑chat‑canvas component—such as Angular or other front‑end applications that use the a2ui library—carries the risk. The issue affects the a2ui‑project a2ui library through version 0.10.7, and the unsafe code resides in samples/community/client/angular/projects/a2a‑chat‑canvas/src/lib/services/sanitizer‑markdown‑renderer‑service.ts.

The CVSS score of 5.1 places the flaw in the medium severity range. The EPSS score of less than 1% indicates a low likelihood of exploitation at the time of measurement, and the vulnerability is not catalogued in KEV. Nevertheless, the attack can be performed remotely by supplying markdown to a victim, so the risk to exposed web applications remains significant.