A stored cross-site scripting (XSS) vulnerability in the U2F Origin field of the Datacenter configuration in Proxmox Virtual Environment (P…

published 2025-09-09 14 mo ago modified 2026-11-08 41 h ago also EUVD-2025-27406

cvss: 5.4; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.3%; EPSS 0.3% chance of exploitation in 30 days, percentile 21%
public exploits: 0; none known

A stored cross-site scripting (XSS) vulnerability in the U2F Origin field of the Datacenter configuration in Proxmox Virtual Environment (PVE) 8.4 allows authenticated users to store malicious input. The payload is rendered unsafely in the Web UI and executed when viewed by other users, potentially leading to session hijacking or other attacks.

CISA SSVC

Exploitation: Proof of concept is public
Automatable: no
Technical impact: partial
Assessed: 13 mo ago (2025-09-10)

Exploit prediction

0.29% chance of exploitation in the next 30 days, higher than 21% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

github.com https://github.com/khankishiyev-j/bug-bounty/blob/main/proxmox-xss referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by	version	score	vector
CISA ADP	3.1	5.4	CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
CNA	3.1	5.4	CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

Classification

Weakness

CWE-79 Improper Neutralization of Input During Web Page Generation

References

github.com /khankishiyev-j/bug-bounty/blob/main/proxmox-xss
exploit, third-party-advisory
forum.proxmox.com /threads/proxmox-virtual-environment-security-advisories.149331/page-2#post-792010
issue-tracking, vendor-advisory
youtube.com /watch?v=-wvkN-7oT5U
broken-link

Sources

CVE List CVE-2025-57539
NVD CVE-2025-57539

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