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Fencer Vulns
critical 9.9

CVE-2026-45558 json

Roxy-WI: Authenticated RCE on every managed HAProxy load balancer via `option` field config injection in section save

published 2026-06-10 4 mo ago modified 2026-06-17 4 mo ago also EUVD-2026-36039

cvss
9.9
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 38%
public exploits
0
none known

Summary

Roxy-WI is a web interface for managing Haproxy, Nginx, Apache and Keepalived servers. In versions 8.2.6.4 and prior, the HAProxy section-save endpoints (POST /api/service/haproxy/<server_id>/section/<section_type> and the PUT / global / defaults variants) accept a JSON option field that is not validated, not escaped, and is rendered verbatim into the generated HAProxy configuration via the section.j2, global.j2, and defaults.j2 Ansible templates. Because Roxy-WI then pushes the generated config to the load balancer and runs systemctl reload haproxy, an authenticated user with role ≤ 3 (user) can inject arbitrary HAProxy directives into the config that runs on every load balancer their group manages — including option external-check + external-check command /bin/bash -c '…', which gives remote code execution on the load balancer as the haproxy user on every health-check tick. At time of publication, there are no publicly available patches.

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
total
Assessed
4 mo ago

Exploit prediction

0.44% chance of exploitation in the next 30 days, higher than 38% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/roxy-wi/roxy-wi/security/advisories/GHSA-w2x4-66jj-3597 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 9.9 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Affected products

  • roxy-wi roxy-wi

Classification

Weakness
  • CWE-20 Improper Input Validation
  • CWE-77 Improper Neutralization of Special Elements used in a Command
  • CWE-78 Improper Neutralization of Special Elements used in an OS Command
  • CWE-94 Improper Control of Generation of Code

References

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.