# CVE-2025-57540: CVE-2025-57540

Status: published. Published: 2025-09-09. Updated: 2026-11-08.

A stored cross-site scripting (XSS) vulnerability exists in the WebAuthn Relying Party field within the Datacenter configuration of Proxmox Virtual Environment (PVE) 8.4. Authenticated users can inject JavaScript code that is later executed in the browsers of users who view the configuration page, enabling client-side attacks.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- proxmox / virtual_environment: 8.4 (affected, custom). Source: NVD

## NVD configuration conditions

Affected CPE matches depend on the following AND/OR and negation conditions:

```json
[
  {
    "negate": false,
    "nodes": [
      {
        "cpeMatch": [
          {
            "criteria": "cpe:2.3:a:proxmox:virtual_environment:8.4:*:*:*:*:*:*:*",
            "vulnerable": true
          }
        ],
        "negate": false,
        "operator": "OR"
      }
    ],
    "operator": "OR"
  }
]
```

## Severity and prioritization

- CVSS 3.1: 5.4 (medium); CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N; source: NVD: 134c704f-9b21-4f2e-91b3-4a467353bcc0

- CISA KEV: No listing in collected sources

- EPSS: Not available

- SSVC: exploitation poc; automatable no; technical impact partial; source NVD SSVC: 134c704f-9b21-4f2e-91b3-4a467353bcc0

- Weaknesses: CWE-79

## Exploit evidence

- exploit: https://github.com/khankishiyev-j/bug-bounty/blob/main/proxmox-xss (cve@mitre.org)
- exploit: https://github.com/khankishiyev-j/bug-bounty/blob/main/proxmox-xss (134c704f-9b21-4f2e-91b3-4a467353bcc0)

## References

- https://forum.proxmox.com/threads/proxmox-virtual-environment-security-advisories.149331/page-2#post-792010 (cve@mitre.org; Issue Tracking, Vendor Advisory)

- https://github.com/khankishiyev-j/bug-bounty/blob/main/proxmox-xss (cve@mitre.org; Exploit, Third Party Advisory)

- https://www.youtube.com/watch?v=-wvkN-7oT5U (cve@mitre.org; Broken Link)

- https://github.com/khankishiyev-j/bug-bounty/blob/main/proxmox-xss (134c704f-9b21-4f2e-91b3-4a467353bcc0; Exploit, Third Party Advisory)

## Provenance

- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-57540; retrieved 2026-11-08; source updated 2026-11-08

Revision: 5f10cff0501073b8beebb81258cf1759631e66356968993b046eab4d02f0a43d

Canonical: https://y2.dev/cve/CVE-2025-57540

## Agent and API access

Public CVE pages, Markdown, and JSON are free to read without an account or API key.

- Public catalog: https://y2.dev/cve/index.json. Follow nextCursor with the same search, filters, sort, and limit (1–100). A null cursor marks the end.

- WebMCP: search_cve_disclosures, get_cve_disclosure, get_cve_page_markdown, get_y2_cve_access. Available in compatible browsers.

- Cyber API: https://api.y2.dev/api/v2/cyber/cves and https://api.y2.dev/api/v2/cyber/cves/{cveId}.

- Y2 Pro or Elite: create a workspace API key with the intel:cyber scope and send Authorization: Bearer <Y2_API_KEY>. Setup: https://y2.dev/docs/api/create-key.

- x402: Pay per request without an account or API key. Omit Authorization, read the HTTP 402 PAYMENT-REQUIRED challenge, validate its current requirements, and retry with PAYMENT-SIGNATURE through an authorized payment client. These browser tools never make payments. Guide: https://y2.dev/docs/api/x402.

- OpenAPI: https://y2.dev/api/openapi.yaml. Agent access metadata: https://y2.dev/cve/agent.json.

Collected public records only. Check source status for coverage and freshness.