CVE-2026-85124

HIGHPre-NVD 7.57.5—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 7.5 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.7%, top 48% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, secondary
7.5EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 1%CVSS: 7.5Exploit: None knownExposed: 0

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

@fastify/http-proxy versions before 11.6.2 do not validate proxied HTTP request paths for backslash based dot-segments before forwarding them to the configured upstream. The plain HTTP request handler skips the destination validation that the WebSocket path performs, and the underlying reply-from library only rejects forward-slash traversal, so a request containing backslash dot-segments can escape the boundary set by the prefix and rewritePrefix options. An unauthenticated network attacker can use this to reach upstream paths that were meant to stay hidden behind the proxy, resulting in disclosure of internal endpoints. This is a path traversal issue (CWE-22). Users should upgrade to @fastify/http-proxy 11.6.2 or later.

CVSS v3
7.5
EG Score
7.5(medium)
EG Risk
49(Track)
EG Risk 49/100SSVC: Track

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%
Exploitation1% × 40%
Automatability100% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
1%
EPSS %ILE
52%
KEV
Not listed

Published

September 3, 2026

Last Modified

September 9, 2026

Advisory Details (2)

Auto-updated Sep 3, 2026
Patch available. Sources: github.
generic

Security Advisories | OpenJS Foundation CVE Numbering Authority

https://cna.openjsf.org/security-advisories.html
github Patch Available

@fastify/http-proxy vulnerable to prefix escape via backslash dot-segments · Advisory · fastify/fastify-http-proxy · GitHub

https://github.com/fastify/fastify-http-proxy/security/advisories/GHSA-qv33-689p-2xq5

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 13× in last 7d / 41× 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.

  1. 2026-09-24 19:08 UTCEG score recompute
  2. 2026-09-24 14:04 UTCEPSS rescore
  3. 2026-09-24 06:22 UTCEG score recompute
  4. 2026-09-23 17:54 UTCEPSS rescore
  5. 2026-09-23 04:38 UTCEG score recompute
  6. 2026-09-22 16:01 UTCEPSS rescore
  7. 2026-09-22 03:05 UTCEG score recompute
  8. 2026-09-21 21:09 UTCEPSS rescore
  9. 2026-09-21 01:31 UTCEG score recompute
  10. 2026-09-20 20:16 UTCEPSS rescore
  11. 2026-09-19 23:41 UTCEG score recompute
  12. 2026-09-18 22:09 UTCEG score recompute
  13. 2026-09-18 19:28 UTCEPSS rescore
  14. 2026-09-17 20:36 UTCEG score recompute
  15. 2026-09-17 19:32 UTCEPSS rescore
  16. 2026-09-16 18:36 UTCEG score recompute
  17. 2026-09-16 14:09 UTCEPSS rescore
  18. 2026-09-16 05:25 UTCEG score recompute
  19. 2026-09-16 05:15 UTCEPSS rescore
  20. 2026-09-15 03:53 UTCEG score recompute
  21. 2026-09-15 03:12 UTCEPSS rescore
  22. 2026-09-15 03:12 UTCEPSS rescore
  23. 2026-09-14 02:21 UTCEG score recompute
  24. 2026-09-13 00:49 UTCEG score recompute
  25. 2026-09-11 23:16 UTCEG score recompute
Show 16 more
  1. 2026-09-11 14:53 UTCEPSS rescore
  2. 2026-09-11 14:53 UTCEPSS rescore
  3. 2026-09-11 09:56 UTCEG score recompute
  4. 2026-09-10 21:10 UTCEG score recompute
  5. 2026-09-08 23:10 UTCEG score recompute
  6. 2026-09-08 22:01 UTCEPSS rescore
  7. 2026-09-08 00:42 UTCEG score recompute
  8. 2026-09-06 23:06 UTCEG score recompute
  9. 2026-09-06 13:48 UTCEPSS rescore
  10. 2026-09-05 21:31 UTCEG score recompute
  11. 2026-09-05 15:31 UTCEPSS rescore
  12. 2026-09-04 19:58 UTCEG score recompute
  13. 2026-09-03 13:15 UTCEG score recompute
  14. 2026-09-03 12:49 UTCEG score recompute
  15. 2026-09-03 10:54 UTCEG score recompute
  16. 2026-09-03 10:54 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-85124?
CVE-2026-85124 is a high vulnerability published on September 3, 2026. @fastify/http-proxy versions before 11.6.2 do not validate proxied HTTP request paths for backslash based dot-segments before forwarding them to the configured upstream. The plain HTTP request handler skips the destination validation that the WebSocket path performs, and the underlying reply-from…
When was CVE-2026-85124 disclosed?
CVE-2026-85124 was first published in the National Vulnerability Database on September 3, 2026, with the most recent update on September 9, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-85124 actively exploited?
CVE-2026-85124 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1% probability of exploitation in the next 30 days, which ranks it in the top 47.5% of all scored CVEs.
What is the CVSS score of CVE-2026-85124?
CVE-2026-85124 has a CVSS v3 base score of 7.5 (NVD).
How do I remediate CVE-2026-85124?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-85124, 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.

Dependency Blast Radius

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