CVE-2026-33805

HIGHNVD 8.68.6—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 8.6 under NVD CVSS v3. EPSS exploit probability: 0.4%, top 63% 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, nvd
Elevated
8.6EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 8.6Exploit: Elevated riskExposed: 0

A fix is available — apply it.

@fastify/reply-from v12.6.1 and earlier and @fastify/http-proxy v11.4.3 and earlier process the client's Connection header after the proxy has added its own headers via rewriteRequestHeaders. This allows attackers to retroactively strip proxy-added headers from upstream requests by listing them in the Connection header value. Any header added by the proxy for routing, access control, or security purposes can be selectively removed by a client. @fastify/http-proxy is also affected as it delegates to @fastify/reply-from.

Upgrade to @fastify/reply-from v12.6.2 or @fastify/http-proxy v11.4.4 or later.

CVSS v3
8.6
EG Score
8.6(medium)
EG Risk
70(Attend)
EG Risk 70/100SSVC: 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
Severity86% × 45%
Exploitation40% × 40%
Automatability100% × 15%
Action: Remediate soon — notable exploitation risk.
EPSS PROB
0%
EPSS %ILE
37%
KEV
Not listed

Published

April 15, 2026

Last Modified

July 15, 2026

Advisory Details (2)

Auto-updated Jun 2, 2026
🔬 Proof of concept available. Patch available. Sources: github.
github Patch Available🟡 PoC Available

Connection header abuse enables stripping of proxy-added headers · Advisory · fastify/fastify-reply-from · GitHub

https://github.com/fastify/fastify-reply-from/security/advisories/GHSA-gwhp-pf74-vj37
generic

Security Advisories | OpenJS Foundation CVE Numbering Authority

https://cna.openjsf.org/security-advisories.html

Vendor Advisories for CVE-2026-33805(2)

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

Patch Availability(1)

Vendor / EcosystemFixed in / PatchReleasedSource
redhatdevspaces/dashboard-rhel9:17767955112026-04-23redhat

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(2 across 1 ecosystem)
npm(2)
PackageVulnerable rangeFixed inDependents
@fastify/http-proxy—11.4.4—
@fastify/reply-from—12.6.2—

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 7× in last 7d / 30× 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 197 total refreshes for this CVE.

  1. 2026-09-15 03:11 UTCEPSS rescore
  2. 2026-09-13 16:47 UTCEPSS rescore
  3. 2026-09-12 15:01 UTCEPSS rescore
  4. 2026-09-11 14:53 UTCEPSS rescore
  5. 2026-09-11 09:37 UTCEPSS rescore
  6. 2026-09-10 09:34 UTCEPSS rescore
  7. 2026-09-08 22:00 UTCEPSS rescore
  8. 2026-09-07 16:01 UTCEPSS rescore
  9. 2026-09-06 13:47 UTCEPSS rescore
  10. 2026-09-04 05:06 UTCEPSS rescore
  11. 2026-09-02 14:12 UTCEPSS rescore
  12. 2026-09-02 04:58 UTCOSV refresh
  13. 2026-09-01 13:53 UTCEPSS rescore
  14. 2026-09-01 04:39 UTCEPSS rescore
  15. 2026-09-01 04:39 UTCEPSS rescore
  16. 2026-08-30 19:17 UTCEPSS rescore
  17. 2026-08-30 01:22 UTCEPSS rescore
  18. 2026-08-28 21:41 UTCEPSS rescore
  19. 2026-08-27 14:25 UTCEPSS rescore
  20. 2026-08-26 14:46 UTCEPSS rescore
  21. 2026-08-25 13:49 UTCEPSS rescore
  22. 2026-08-24 14:17 UTCEPSS rescore
  23. 2026-08-23 00:19 UTCEPSS rescore
  24. 2026-08-21 23:49 UTCEPSS rescore
  25. 2026-08-20 22:55 UTCEPSS rescore
Show 75 more
  1. 2026-08-20 22:55 UTCEPSS rescore
  2. 2026-08-19 17:03 UTCEPSS rescore
  3. 2026-08-18 13:48 UTCEPSS rescore
  4. 2026-08-17 13:47 UTCEPSS rescore
  5. 2026-08-16 14:56 UTCEPSS rescore
  6. 2026-08-16 06:41 UTCEG score recompute
  7. 2026-08-16 06:41 UTCVendor advisory
  8. 2026-08-16 02:14 UTCEPSS rescore
  9. 2026-08-15 01:30 UTCEPSS rescore
  10. 2026-08-14 18:13 UTCVendor advisory
  11. 2026-08-14 04:46 UTCEG score recompute
  12. 2026-08-14 04:46 UTCVendor advisory
  13. 2026-08-13 22:00 UTCEPSS rescore
  14. 2026-08-13 08:57 UTCVendor advisory
  15. 2026-08-12 18:57 UTCEG score recompute
  16. 2026-08-12 18:57 UTCVendor advisory
  17. 2026-08-12 13:50 UTCEPSS rescore
  18. 2026-08-11 18:52 UTCEG score recompute
  19. 2026-08-11 18:52 UTCVendor advisory
  20. 2026-08-11 02:40 UTCEG score recompute
  21. 2026-08-11 02:40 UTCVendor advisory
  22. 2026-08-11 00:00 UTCEPSS rescore
  23. 2026-08-10 03:26 UTCVendor advisory
  24. 2026-08-09 15:45 UTCEG score recompute
  25. 2026-08-09 15:45 UTCVendor advisory
  26. 2026-08-09 13:46 UTCEPSS rescore
  27. 2026-08-09 04:03 UTCEG score recompute
  28. 2026-08-09 04:03 UTCVendor advisory
  29. 2026-08-08 16:37 UTCEPSS rescore
  30. 2026-08-08 01:14 UTCEG score recompute
  31. 2026-08-08 01:14 UTCVendor advisory
  32. 2026-08-07 13:33 UTCEG score recompute
  33. 2026-08-07 13:33 UTCVendor advisory
  34. 2026-08-06 13:46 UTCEPSS rescore
  35. 2026-08-06 12:12 UTCVendor advisory
  36. 2026-08-05 23:25 UTCEG score recompute
  37. 2026-08-05 23:25 UTCVendor advisory
  38. 2026-08-05 19:17 UTCEPSS rescore
  39. 2026-08-04 15:10 UTCEPSS rescore
  40. 2026-08-04 10:38 UTCEPSS rescore
  41. 2026-08-03 21:37 UTCEG score recompute
  42. 2026-08-03 21:37 UTCVendor advisory
  43. 2026-08-03 10:36 UTCEPSS rescore
  44. 2026-08-03 00:59 UTCVendor advisory
  45. 2026-08-02 13:17 UTCEG score recompute
  46. 2026-08-02 13:17 UTCVendor advisory
  47. 2026-08-02 02:27 UTCEPSS rescore
  48. 2026-08-01 04:16 UTCEPSS rescore
  49. 2026-07-30 16:28 UTCEPSS rescore
  50. 2026-07-30 01:30 UTCEPSS rescore
  51. 2026-07-27 14:13 UTCEPSS rescore
  52. 2026-07-26 14:54 UTCEPSS rescore
  53. 2026-07-26 14:54 UTCEPSS rescore
  54. 2026-07-25 14:18 UTCEPSS rescore
  55. 2026-07-25 14:18 UTCEPSS rescore
  56. 2026-07-24 14:17 UTCEPSS rescore
  57. 2026-07-24 14:17 UTCEPSS rescore
  58. 2026-07-23 14:18 UTCEPSS rescore
  59. 2026-07-23 14:18 UTCEPSS rescore
  60. 2026-07-23 03:09 UTCEG score recompute
  61. 2026-07-22 14:08 UTCEPSS rescore
  62. 2026-07-21 15:24 UTCEPSS rescore
  63. 2026-07-20 17:08 UTCEPSS rescore
  64. 2026-07-20 10:04 UTCOSV refresh
  65. 2026-07-19 14:31 UTCEPSS rescore
  66. 2026-07-19 02:29 UTCEPSS rescore
  67. 2026-07-18 10:04 UTCEPSS rescore
  68. 2026-07-16 17:03 UTCEPSS rescore
  69. 2026-07-15 16:57 UTCEPSS rescore
  70. 2026-07-15 16:57 UTCEPSS rescore
  71. 2026-07-15 02:23 UTCNVD updateCVSS v3 → 8.6
  72. 2026-07-15 02:00 UTCEPSS rescore
  73. 2026-07-15 01:21 UTCMITRE cvelistV5CVSS v3 → 7.4
  74. 2026-07-13 22:30 UTCEPSS rescore
  75. 2026-07-13 06:13 UTCEPSS rescore

Frequently asked(5)

What is CVE-2026-33805?
CVE-2026-33805 is a high vulnerability published on April 15, 2026. @fastify/reply-from v12.6.1 and earlier and @fastify/http-proxy v11.4.3 and earlier process the client's Connection header after the proxy has added its own headers via rewriteRequestHeaders. This allows attackers to retroactively strip proxy-added headers from upstream requests by listing them in…
When was CVE-2026-33805 disclosed?
CVE-2026-33805 was first published in the National Vulnerability Database on April 15, 2026, with the most recent update on July 15, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-33805 actively exploited?
CVE-2026-33805 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 62.8% of all scored CVEs.
What is the CVSS score of CVE-2026-33805?
CVE-2026-33805 has a CVSS v3 base score of 8.6 (NVD).
How do I remediate CVE-2026-33805?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-33805, 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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