CVE-2026-16221

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: 0.4%, 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, secondary
Trending — Patch released this week
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: None knownExposed: 0

A fix is available — apply it.

Impact: fast-uri versions from 2.3.1 through 4.1.0 (including the 3.x line up to 3.1.3 and the 2.x line up to 2.4.2) do not treat a literal backslash character (U+005C) as an authority delimiter. Node's native WHATWG URL parser, used by fetch, undici, and Node's http and https clients, normalizes the backslash to a forward slash for special schemes such as http, https, ws, wss, ftp, and file. As a result, the two parsers extract different hosts from the same input string. Applications that use fast-uri to enforce host-based policy such as allowlists, denylists, loopback or SSRF filtering, redirect validation, or outbound proxy routing before passing the same URL into Node's URL or fetch consumers can be steered to an unintended destination, including cloud metadata endpoints, loopback, or internal hosts.

Patches: upgrade to fast-uri 4.1.1, 3.1.4, or 2.4.3.

Workarounds: none.

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%
Exploitation0% × 40%
Automatability100% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
37%
KEV
Not listed

Published

July 19, 2026

Last Modified

August 5, 2026

Advisory Details (2)

Auto-updated Jul 19, 2026
Patch available. Sources: github.
github Patch Available

fast-uri vulnerable to host confusion via literal backslash authority delimiter · Advisory · fastify/fast-uri · GitHub

https://github.com/fastify/fast-uri/security/advisories/GHSA-v2hh-gcrm-f6hx
generic

Security Advisories | OpenJS Foundation CVE Numbering Authority

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

Vendor Advisories for CVE-2026-16221(5)

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

Patch Availability(4)

Vendor / EcosystemFixed in / PatchReleasedSource
redhatodf4/rook-ceph-rhel9-operator:17881648572026-09-08redhat
redhatquay/quay-rhel8:17885955742026-09-08redhat
redhatgrafana13-1-main-13.1.3-0.1.1.hum12026-08-13redhat
redhatgrafana12-4-main-12.4.8-0.1.1.hum12026-08-13redhat

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

(3 across 3 ecosystems)
Debian:13(1)
PackageVulnerable rangeFixed inDependents
node-ajv8.12.0~ds+~2.1.1-5 ... 8.20.0~ds+~cs7.1.4-1 (13 versions)——
Debian:14(1)
PackageVulnerable rangeFixed inDependents
node-ajv8.12.0~ds+~2.1.1-5 ... 8.20.0~ds+~cs6.1.3-1 (8 versions)8.20.0~ds+~cs7.1.2-1—
npm(1)
PackageVulnerable rangeFixed inDependents
fast-uri—4.1.1—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 13× in last 7d / 69× 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 117 total refreshes for this CVE.

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

Frequently asked(5)

What is CVE-2026-16221?
CVE-2026-16221 is a high vulnerability published on July 19, 2026. Impact: fast-uri versions from 2.3.1 through 4.1.0 (including the 3.x line up to 3.1.3 and the 2.x line up to 2.4.2) do not treat a literal backslash character (U+005C) as an authority delimiter. Node's native WHATWG URL parser, used by fetch, undici, and Node's http and https clients, normalizes…
When was CVE-2026-16221 disclosed?
CVE-2026-16221 was first published in the National Vulnerability Database on July 19, 2026, with the most recent update on August 5, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-16221 actively exploited?
CVE-2026-16221 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 63.2% of all scored CVEs.
What is the CVSS score of CVE-2026-16221?
CVE-2026-16221 has a CVSS v3 base score of 7.5 (NVD).
How do I remediate CVE-2026-16221?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-16221, 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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