CVE-2026-43634: high-severity vulnerability in hestiacp
HestiaCP 1.2.0-1.9.4 IP Spoofing via CF-Connecting-IP Header
Published · Updated
41Vexday Risk Score
No sign of exploitation. It has a public proof of concept.
ssvc Attendcvss 8.7epss 0.4%
exploitation probability
0.4%top 72% of all CVEs
observed exploitation
nono source reports it
1 public exploit(s)
HestiaCP versions 1.2.0 through 1.9.4 contain an IP spoofing vulnerability that allows unauthenticated remote attackers to bypass authentication security controls by supplying an arbitrary IP address in the CF-Connecting-IP HTTP header without verifying the request originated from Cloudflare's network. Attackers can exploit this to circumvent fail2ban brute-force protection, bypass per-user IP allowlists, and poison authentication audit logs by spoofing trusted IP addresses on each request.
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N
Affected products
hestiacp · hestiacppublic PoCs found — 1
cve_referencemercuryiss.com.au/hestiacp-unauthenticated-rce-ip-spoofing-cve-2026-43633-cve-2026-43634unverified⚠ Public resources, to assess the exposure of systems you control or are authorized to test. Test only with authorization.
Related CVEs — hestiacp
In the same product, most dangerous first.
CVE-2025-30007HIGHHestiaCP < 1.9.5 Authenticated OS Command Injection via DNS Record ManagementEPSS 3.2%CVE-2026-43633CRITICALHestiaCP 1.9.0-1.9.4 Deserialization RCE via Web TerminalEPSS 1.5%CVE-2026-12196HIGHHestiaCP Admin TakeoverEPSS 0.4%CVE-2025-30008MEDIUMHestiaCP < 1.9.5 Stored XSS via DNS Record Management InterfaceEPSS 0.3%
References
https://github.com/hestiacp/hestiacp/commit/f381e294500f671cf12716c638afd0bfde901f88https://github.com/hestiacp/hestiacp/issues/5229https://github.com/hestiacp/hestiacp/pull/5273https://mercuryiss.com.au/hestiacp-unauthenticated-rce-ip-spoofing-cve-2026-43633-cve-2026-43634https://www.vulncheck.com/advisories/hestiacp-ip-spoofing-via-cf-connecting-ip-header