Arbitrary JavaScript Execution via openUrl in @a2ui/web_core

published 2026-08-04 3 mo ago modified 2026-10-23 16 d ago also GHSA-72qq-p3r5-f7wq , EUVD-2026-52744

cvss: 6.1; version 3.1, NVD
cisa kev: Not listed; not in CISA's catalog
epss: 0.1%; EPSS 0.1% chance of exploitation in 30 days, percentile 2%
public exploits: 0; none known

The openUrl function in @a2ui/web_core passes an agent-controlled URL directly to window.open() without validating the URI scheme. A malicious agent can supply a javascript: URI as the url argument of a Button component's functionCall action. When the user clicks the rendered button, arbitrary JavaScript executes in the victim application's browser origin, constituting a stored/reflected XSS with Critical severity. No non-default configuration is required; the Basic Catalog is enabled by default.

Patch / fix

fixed in 2 links 2

npm @a2ui/web_core 0.10.2
google a2ui/web_core 0.10.2

github.com/a2ui-project/a2ui@7157307 commit
github.com/a2ui-project/a2ui#1707 pull request

CISA SSVC

Exploitation: none
Automatable: no
Technical impact: total
Assessed: 3 mo ago (2026-08-04)

Exploit prediction

0.13% chance of exploitation in the next 30 days, higher than 2% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	4.0	6.1	CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:H/VI:H/VA:L/SC:N/SI:N/SA:N/E:U
CNA	4.0	6.1	CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:H/VI:H/VA:L/SC:N/SI:N/SA:N/E:U/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
NVD	3.1	6.1	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
GitHub	3.1	9.3	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N

Affected packages

ecosystem	package	affected	fixed in
npm	@a2ui/web_core	>=0.9.0, <0.10.2	0.10.2

Affected products

Google @a2ui/web_core

Classification

Weakness

CWE-79 Improper Neutralization of Input During Web Page Generation

References

github.com /a2ui-project/a2ui/pull/1707
web
github.com /a2ui-project/a2ui/commit/71573078c4168b2dc166bb847c3a85715dadc675
web
github.com /a2ui-project/a2ui/security/advisories/GHSA-72qq-p3r5-f7wq
web, vendor-advisory
nvd.nist.gov /vuln/detail/CVE-2026-10032
advisory
github.com /a2ui-project/a2ui
package

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary