CVE-2026-43634

HIGHPre-NVD 7.57.5—
EchelonGraph scoreMEDIUM confidence

Score 7.5 from GitHub Security Advisory (severity: HIGH) published 2026-05-19. a secondary CVSS source baseline 7.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Elevated
7.5EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 7.5Exploit: Elevated riskExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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 v3
7.5
EG Score
7.5(medium)
EG Risk
65(Attend)
EG Risk 65/100SSVC: Attend

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity75% × 45%
Exploitation40% × 40%
Automatability100% × 15%
Action: Remediate soon — notable exploitation risk.
EPSS PROB
0%
EPSS %ILE
16%
KEV
Not listed

Published

May 19, 2026

Last Modified

July 24, 2026

Advisory Details (5)

Auto-updated Jun 9, 2026
Patch available. Sources: github_commit, github_pr.
generic

HestiaCP 1.2.0-1.9.4 IP Spoofing via CF-Connecting-IP Header | Advisories | VulnCheck

https://www.vulncheck.com/advisories/hestiacp-ip-spoofing-via-cf-connecting-ip-header
generic

Unauthenticated RCE and IP Spoofing in HestiaCP | Mercury ISS

https://mercuryiss.com.au/hestiacp-unauthenticated-rce-ip-spoofing-cve-2026-43633-cve-2026-43634
github_pr Patch Available

Stop trusting unauthenticated proxy headers

Patch available: hestiacp/hestiacp 1.9.6 (PR #5273 merged 2026-03-24)

https://github.com/hestiacp/hestiacp/pull/5273
generic

Security vulnerability in Hestia CP · Issue #5229 · hestiacp/hestiacp · GitHub

https://github.com/hestiacp/hestiacp/issues/5229
github_commit Patch Available

commit f381e294500f (hestiacp/hestiacp)

Patch available: hestiacp/hestiacp 1.9.6 (contains commit f381e294500f)

https://github.com/hestiacp/hestiacp/commit/f381e294500f671cf12716c638afd0bfde901f88

Vendor Advisories for CVE-2026-43634(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 6× in last 7d / 31× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 220 total refreshes for this CVE.

  1. 2026-09-18 19:28 UTCEPSS rescore
  2. 2026-09-17 19:31 UTCEPSS rescore
  3. 2026-09-16 14:08 UTCEPSS rescore
  4. 2026-09-16 05:15 UTCEPSS rescore
  5. 2026-09-13 16:47 UTCEPSS rescore
  6. 2026-09-12 15:01 UTCEPSS rescore
  7. 2026-09-11 14:53 UTCEPSS rescore
  8. 2026-09-11 09:37 UTCEPSS rescore
  9. 2026-09-11 05:53 UTCOSV refresh
  10. 2026-09-10 09:34 UTCEPSS rescore
  11. 2026-09-08 22:00 UTCEPSS rescore
  12. 2026-09-07 16:01 UTCEPSS rescore
  13. 2026-09-06 13:47 UTCEPSS rescore
  14. 2026-09-04 05:06 UTCEPSS rescore
  15. 2026-09-02 14:12 UTCEPSS rescore
  16. 2026-09-01 13:54 UTCEPSS rescore
  17. 2026-08-30 19:17 UTCEPSS rescore
  18. 2026-08-30 01:22 UTCEPSS rescore
  19. 2026-08-28 21:41 UTCEPSS rescore
  20. 2026-08-27 14:25 UTCEPSS rescore
  21. 2026-08-26 14:46 UTCEPSS rescore
  22. 2026-08-25 13:49 UTCEPSS rescore
  23. 2026-08-23 17:01 UTCEG score recompute
  24. 2026-08-23 17:01 UTCGHSA enrichment
  25. 2026-08-23 00:19 UTCEPSS rescore
Show 75 more
  1. 2026-08-21 23:49 UTCEPSS rescore
  2. 2026-08-21 23:38 UTCEG score recompute
  3. 2026-08-21 23:38 UTCGHSA enrichment
  4. 2026-08-20 22:55 UTCEPSS rescore
  5. 2026-08-20 19:02 UTCEG score recompute
  6. 2026-08-20 19:02 UTCGHSA enrichment
  7. 2026-08-19 17:04 UTCEPSS rescore
  8. 2026-08-18 13:48 UTCEPSS rescore
  9. 2026-08-17 13:47 UTCEPSS rescore
  10. 2026-08-17 10:00 UTCEG score recompute
  11. 2026-08-17 10:00 UTCGHSA enrichment
  12. 2026-08-16 14:56 UTCEPSS rescore
  13. 2026-08-16 03:35 UTCEG score recompute
  14. 2026-08-16 03:35 UTCGHSA enrichment
  15. 2026-08-16 02:14 UTCEPSS rescore
  16. 2026-08-15 03:25 UTCEG score recompute
  17. 2026-08-15 03:25 UTCGHSA enrichment
  18. 2026-08-15 01:30 UTCEPSS rescore
  19. 2026-08-14 14:21 UTCGHSA enrichment
  20. 2026-08-14 02:07 UTCEG score recompute
  21. 2026-08-14 02:07 UTCGHSA enrichment
  22. 2026-08-13 22:00 UTCEPSS rescore
  23. 2026-08-13 02:37 UTCGHSA enrichment
  24. 2026-08-12 14:22 UTCEG score recompute
  25. 2026-08-12 14:22 UTCGHSA enrichment
  26. 2026-08-12 13:51 UTCEPSS rescore
  27. 2026-08-12 02:08 UTCGHSA enrichment
  28. 2026-08-11 13:53 UTCEG score recompute
  29. 2026-08-11 13:53 UTCGHSA enrichment
  30. 2026-08-11 13:43 UTCEPSS rescore
  31. 2026-08-11 00:39 UTCEG score recompute
  32. 2026-08-11 00:39 UTCGHSA enrichment
  33. 2026-08-11 00:00 UTCEPSS rescore
  34. 2026-08-10 02:47 UTCGHSA enrichment
  35. 2026-08-09 14:32 UTCEG score recompute
  36. 2026-08-09 14:32 UTCGHSA enrichment
  37. 2026-08-09 13:46 UTCEPSS rescore
  38. 2026-08-09 02:18 UTCEG score recompute
  39. 2026-08-09 02:18 UTCGHSA enrichment
  40. 2026-08-08 16:37 UTCEPSS rescore
  41. 2026-08-08 14:03 UTCGHSA enrichment
  42. 2026-08-08 01:39 UTCEG score recompute
  43. 2026-08-08 01:39 UTCGHSA enrichment
  44. 2026-08-07 13:24 UTCGHSA enrichment
  45. 2026-08-07 01:09 UTCEG score recompute
  46. 2026-08-07 01:09 UTCGHSA enrichment
  47. 2026-08-06 13:46 UTCEPSS rescore
  48. 2026-08-06 09:36 UTCGHSA enrichment
  49. 2026-08-05 21:21 UTCEG score recompute
  50. 2026-08-05 21:21 UTCGHSA enrichment
  51. 2026-08-05 19:17 UTCEPSS rescore
  52. 2026-08-04 15:10 UTCEPSS rescore
  53. 2026-08-04 10:38 UTCEPSS rescore
  54. 2026-08-04 05:27 UTCGHSA enrichment
  55. 2026-08-03 16:58 UTCEG score recompute
  56. 2026-08-03 16:58 UTCGHSA enrichment
  57. 2026-08-03 10:36 UTCEPSS rescore
  58. 2026-08-02 19:12 UTCGHSA enrichment
  59. 2026-08-02 06:57 UTCEG score recompute
  60. 2026-08-02 06:57 UTCGHSA enrichment
  61. 2026-08-02 02:27 UTCEPSS rescore
  62. 2026-08-01 17:56 UTCEG score recompute
  63. 2026-08-01 17:56 UTCGHSA enrichment
  64. 2026-08-01 04:16 UTCEPSS rescore
  65. 2026-07-30 16:28 UTCEPSS rescore
  66. 2026-07-30 01:30 UTCEPSS rescore
  67. 2026-07-28 15:36 UTCEPSS rescore
  68. 2026-07-27 14:13 UTCEPSS rescore
  69. 2026-07-26 14:54 UTCEPSS rescore
  70. 2026-07-26 14:54 UTCEPSS rescore
  71. 2026-07-26 08:20 UTCEG score recompute
  72. 2026-07-26 08:20 UTCGHSA enrichment
  73. 2026-07-25 14:18 UTCEPSS rescore
  74. 2026-07-24 14:17 UTCEPSS rescore
  75. 2026-07-23 14:18 UTCEPSS rescore

Frequently asked(5)

What is CVE-2026-43634?
CVE-2026-43634 is a high vulnerability published on May 19, 2026. 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…
When was CVE-2026-43634 disclosed?
CVE-2026-43634 was first published in the National Vulnerability Database on May 19, 2026, with the most recent update on July 24, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-43634 actively exploited?
CVE-2026-43634 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 84.4% of all scored CVEs.
What is the CVSS score of CVE-2026-43634?
CVE-2026-43634 has a CVSS v3 base score of 7.5 (NVD).
How do I remediate CVE-2026-43634?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-43634, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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