CVE-2026-34230

HIGHNVD 7.57.5—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 7.5 under NVD CVSS v3. EPSS exploit probability: 0.4%, top 64% 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
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.

Rack is a modular Ruby web server interface. Prior to versions 2.2.23, 3.1.21, and 3.2.6, Rack::Utils.select_best_encoding processes Accept-Encoding values with quadratic time complexity when the header contains many wildcard (*) entries. Because this method is used by Rack::Deflater to choose a response encoding, an unauthenticated attacker can send a single request with a crafted Accept-Encoding header and cause disproportionate CPU consumption on the compression middleware path. This results in a denial of service condition for applications using Rack::Deflater. This issue has been patched in versions 2.2.23, 3.1.21, and 3.2.6.

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
36%
KEV
Not listed

Published

April 2, 2026

Last Modified

July 24, 2026

Advisory Details (1)

Auto-updated Jul 24, 2026
Patch available. Sources: github.
github Patch Available

Quadratic complexity in `Rack::Utils.select_best_encoding` via wildcard `Accept-Encoding` header. · Advisory · rack/rack · GitHub

https://github.com/rack/rack/security/advisories/GHSA-v569-hp3g-36wr

Patch Availability(1)

Vendor / EcosystemFixed in / PatchReleasedSource
ubunturuby-rack (1.6.4-4ubuntu0.2+esm10) @ bionic2026-07-26ubuntu

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

(5 across 5 ecosystems)
Debian:11(1)
PackageVulnerable rangeFixed inDependents
ruby-rack2.1.4-3 ... 2.1.4-3+deb11u5 (6 versions)2.1.4-3+deb11u6—
Debian:12(1)
PackageVulnerable rangeFixed inDependents
ruby-rack2.2.13-1~deb12u1 ... 2.2.7-1.1 (7 versions)2.2.22-0+deb12u2—
Debian:13(1)
PackageVulnerable rangeFixed inDependents
ruby-rack3.1.16-0.1 ... 3.2.6-3 (10 versions)——
Debian:14(1)
PackageVulnerable rangeFixed inDependents
ruby-rack3.1.16-0.1 ... 3.2.6-1 (7 versions)3.2.6-2—
RubyGems(1)
PackageVulnerable rangeFixed inDependents
rack3.2.0 ... 3.2.5 (6 versions)3.2.6—

Weakness Classification(2)

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

All Vendor Advisories

(1)

Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.

Data Freshness Timeline

(refreshed 7× 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 187 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 11:34 UTCOSV refresh
  13. 2026-09-01 13:53 UTCEPSS rescore
  14. 2026-09-01 04:39 UTCEPSS rescore
  15. 2026-08-30 19:17 UTCEPSS rescore
  16. 2026-08-30 01:22 UTCEPSS rescore
  17. 2026-08-28 21:41 UTCEPSS rescore
  18. 2026-08-27 14:25 UTCEPSS rescore
  19. 2026-08-26 14:46 UTCEPSS rescore
  20. 2026-08-25 13:49 UTCEPSS rescore
  21. 2026-08-24 14:17 UTCEPSS rescore
  22. 2026-08-23 00:19 UTCEPSS rescore
  23. 2026-08-21 23:49 UTCEPSS rescore
  24. 2026-08-20 22:55 UTCEPSS rescore
  25. 2026-08-20 22:55 UTCEPSS rescore
Show 75 more
  1. 2026-08-19 17:03 UTCEPSS rescore
  2. 2026-08-18 13:48 UTCEPSS rescore
  3. 2026-08-17 13:47 UTCEPSS rescore
  4. 2026-08-16 14:56 UTCEPSS rescore
  5. 2026-08-16 09:23 UTCEG score recompute
  6. 2026-08-16 09:23 UTCVendor advisory
  7. 2026-08-16 02:14 UTCEPSS rescore
  8. 2026-08-15 01:30 UTCEPSS rescore
  9. 2026-08-14 18:54 UTCVendor advisory
  10. 2026-08-14 05:49 UTCEG score recompute
  11. 2026-08-14 05:49 UTCVendor advisory
  12. 2026-08-13 22:00 UTCEPSS rescore
  13. 2026-08-13 09:58 UTCVendor advisory
  14. 2026-08-12 20:07 UTCEG score recompute
  15. 2026-08-12 20:07 UTCVendor advisory
  16. 2026-08-12 13:50 UTCEPSS rescore
  17. 2026-08-11 20:28 UTCEG score recompute
  18. 2026-08-11 20:28 UTCVendor advisory
  19. 2026-08-11 03:29 UTCEG score recompute
  20. 2026-08-11 03:29 UTCVendor advisory
  21. 2026-08-11 00:00 UTCEPSS rescore
  22. 2026-08-10 05:31 UTCVendor advisory
  23. 2026-08-09 17:26 UTCEG score recompute
  24. 2026-08-09 17:26 UTCVendor advisory
  25. 2026-08-09 13:46 UTCEPSS rescore
  26. 2026-08-09 05:20 UTCEG score recompute
  27. 2026-08-09 05:20 UTCVendor advisory
  28. 2026-08-08 16:37 UTCEPSS rescore
  29. 2026-08-08 03:32 UTCEG score recompute
  30. 2026-08-08 03:32 UTCVendor advisory
  31. 2026-08-07 15:27 UTCVendor advisory
  32. 2026-08-06 17:45 UTCEG score recompute
  33. 2026-08-06 17:45 UTCVendor advisory
  34. 2026-08-06 13:46 UTCEPSS rescore
  35. 2026-08-06 00:24 UTCEG score recompute
  36. 2026-08-06 00:24 UTCVendor advisory
  37. 2026-08-05 19:17 UTCEPSS rescore
  38. 2026-08-04 15:10 UTCEPSS rescore
  39. 2026-08-04 10:38 UTCEPSS rescore
  40. 2026-08-03 22:43 UTCEG score recompute
  41. 2026-08-03 22:43 UTCVendor advisory
  42. 2026-08-03 10:36 UTCEPSS rescore
  43. 2026-08-03 02:57 UTCVendor advisory
  44. 2026-08-02 14:41 UTCEG score recompute
  45. 2026-08-02 14:41 UTCVendor advisory
  46. 2026-08-02 02:27 UTCEPSS rescore
  47. 2026-08-01 04:16 UTCEPSS rescore
  48. 2026-07-30 16:28 UTCEPSS rescore
  49. 2026-07-30 01:30 UTCEPSS rescore
  50. 2026-07-27 14:13 UTCEPSS rescore
  51. 2026-07-26 14:54 UTCEPSS rescore
  52. 2026-07-26 14:54 UTCEPSS rescore
  53. 2026-07-26 09:28 UTCEG score recompute▲ 2.20
  54. 2026-07-26 09:28 UTCVendor advisory
  55. 2026-07-25 14:18 UTCEPSS rescore
  56. 2026-07-25 14:18 UTCEPSS rescore
  57. 2026-07-24 22:12 UTCNVD updateCVSS v3 → 7.5 · severity → HIGH
  58. 2026-07-24 14:17 UTCEPSS rescore
  59. 2026-07-24 14:17 UTCEPSS rescore
  60. 2026-07-23 14:18 UTCEPSS rescore
  61. 2026-07-23 14:18 UTCEPSS rescore
  62. 2026-07-23 03:09 UTCEG score recompute
  63. 2026-07-22 14:08 UTCEPSS rescore
  64. 2026-07-21 15:24 UTCEPSS rescore
  65. 2026-07-20 17:08 UTCEPSS rescore
  66. 2026-07-19 02:29 UTCEPSS rescore
  67. 2026-07-18 10:04 UTCEPSS rescore
  68. 2026-07-17 03:24 UTCOSV refresh
  69. 2026-07-16 17:03 UTCEPSS rescore
  70. 2026-07-15 16:57 UTCEPSS rescore
  71. 2026-07-15 16:57 UTCEPSS rescore
  72. 2026-07-15 02:00 UTCEPSS rescore
  73. 2026-07-13 22:30 UTCEPSS rescore
  74. 2026-07-13 06:13 UTCEPSS rescore
  75. 2026-07-13 06:13 UTCEPSS rescore

Frequently asked(5)

What is CVE-2026-34230?
CVE-2026-34230 is a high vulnerability published on April 2, 2026. Rack is a modular Ruby web server interface. Prior to versions 2.2.23, 3.1.21, and 3.2.6, Rack::Utils.selectbestencoding processes Accept-Encoding values with quadratic time complexity when the header contains many wildcard (*) entries. Because this method is used by Rack::Deflater to choose a…
When was CVE-2026-34230 disclosed?
CVE-2026-34230 was first published in the National Vulnerability Database on April 2, 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-2026-34230 actively exploited?
CVE-2026-34230 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 63.7% of all scored CVEs.
What is the CVSS score of CVE-2026-34230?
CVE-2026-34230 has a CVSS v3 base score of 7.5 (NVD).
How do I remediate CVE-2026-34230?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-34230, 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

See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-34230

Explore →

Is Your Infrastructure Affected by CVE-2026-34230?

EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.

Start Free Scan →Browse All CVEs