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Fencer Vulns
critical 9.9

CVE-2026-45556 json

Roxy-WI: Authenticated arbitrary file write on every managed load balancer (and downstream RCE) via WAF rule save `config_file_name`

published 2026-06-10 4 mo ago modified 2026-06-17 4 mo ago also EUVD-2026-36038

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 31%
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, POST /waf/<service>/<server_ip>/rule/<rule_id>/save accepts a config_file_name form field that is passed straight through to config_mod.master_slave_upload_and_restart(...) as the destination path. The validation chain (_replace_config_path_to_correct → check_is_conf) only requires the path to contain a hard-coded service substring (nginx/haproxy/apache2/httpd/keepalived) and the substring conf or cfg, and to not contain ... The encoded-slash substitution 92 → / is applied before the substring check, so the attacker can build any absolute path anywhere on the LB filesystem as long as it satisfies those substring constraints. The body of the WAF rule (config form field) is written verbatim to that path. By choosing a filename like 92etc92cron.d92nginx_cfg_evil (resolving to /etc/cron.d/nginx_cfg_evil), an attacker drops a cron entry on the load balancer with attacker-controlled content. Cron parses the file on its next scan, executing the embedded job as root — full RCE on every load balancer the caller's group manages. 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

0.37% chance of exploitation in the next 30 days, higher than 31% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/roxy-wi/roxy-wi/security/advisories/GHSA-85gm-773v-x7m4 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-22 Improper Limitation of a Pathname to a Restricted Directory
  • CWE-73 External Control of File Name or Path
  • CWE-78 Improper Neutralization of Special Elements used in an OS Command

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.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.