CVE-2026-43634 json
HestiaCP 1.2.0-1.9.4 IP Spoofing via CF-Connecting-IP Header
published 2026-05-19 5 mo ago modified 2026-11-08 23 h ago also EUVD-2026-30935
- cvss
- 7.5
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.2%
- EPSS 0.2% chance of exploitation in 30 days, percentile 15%
- public exploits
- 0
- none known
Summary
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.
Patch / fix
- hestiacp control_panel 1.9.5
- github.com/hestiacp/hestiacp@f381e29 commit
- github.com/hestiacp/hestiacp#5273 pull request
CISA SSVC
- Exploitation
- Proof of concept is public
- Automatable
- yes
- Technical impact
- partial
- Assessed
- 5 mo ago
Exploit prediction
0.24% chance of exploitation in the next 30 days, higher than 15% of all scored CVEs (FIRST EPSS, 2026-11-08).
Exploits and checks
- mercuryiss.com.au https://mercuryiss.com.au/hestiacp-unauthenticated-rce-ip-spoofing-cve-2026-43633-cve-2026-43634 referenced PoC, tagged "exploit" by a source, unverified
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 4.0 | 8.7 | 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 |
| CNA | 3.1 | 7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N |
| CNA | 4.0 | 8.7 | 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X |
Affected products
- hestiacp hestiacp
Classification
- Weakness
-
- CWE-348 Use of Less Trusted Source
References
-
github.com
/hestiacp/hestiacp/pull/5273
issue-tracking, patch
-
github.com
/hestiacp/hestiacp/commit/f381e294500f671cf12716c638afd0bfde901f88
patch
-
mercuryiss.com.au
/hestiacp-unauthenticated-rce-ip-spoofing-cve-2026-43633-cve-2026-43634
technical-description, exploit
-
github.com
/hestiacp/hestiacp/issues/5229
issue-tracking
-
vulncheck.com
/advisories/hestiacp-ip-spoofing-via-cf-connecting-ip-header
third-party-advisory
Sources
- CVE List CVE-2026-43634
- NVD CVE-2026-43634
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.