CVE-2026-28368

CRITICALNVD 9.19.1—
EchelonGraph scoreMEDIUM confidence

This critical-severity CVE scores 9.1 under NVD CVSS v3. EPSS exploit probability: 0.7%, top 50% of all CVEs by exploit prediction. GitHub Security Advisory enrichment pending alignment with NVD CVSS.

Triggered by: NVD CVSS baseline
Sources: epss, ghsa, nvd
9.1EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 1%CVSS: 9.1Exploit: None knownExposed: 0

A fix is available — apply it.

A flaw was found in Undertow. This vulnerability allows a remote attacker to construct specially crafted requests where header names are parsed differently by Undertow compared to upstream proxies. This discrepancy in header interpretation can be exploited to launch request smuggling attacks, potentially bypassing security controls and accessing unauthorized resources.

CVSS v3
9.1
EG Score
9.1(medium)
EG Risk
41(Track)
EG Risk 41/100SSVC: 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
Severity91% × 45%
Exploitation1% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
1%
EPSS %ILE
52%
KEV
Not listed

Published

March 27, 2026

Last Modified

June 29, 2026

Advisory Details (4)

Auto-updated Sep 16, 2026
Patch available. Sources: redhat.
redhat Patch Available

2443261 – (CVE-2026-28368) CVE-2026-28368 undertow: Undertow: Request smuggling via inconsistent header parsing

https://bugzilla.redhat.com/show_bug.cgi?id=2443261
redhat Patch Available

CVE-2026-28368 - Red Hat Customer Portal

Affected: Red Hat Enterprise Linux 8 or OpenShift Container Platform 4, is affected by this vulnerability and a fix may be released to a

https://access.redhat.com/security/cve/CVE-2026-28368
redhat Patch Available
https://access.redhat.com/errata/RHSA-2026:25126
redhat Patch Available
https://access.redhat.com/errata/RHSA-2026:25125

Vendor Advisories for CVE-2026-28368(3)

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

Patch Availability(3)

Vendor / EcosystemFixed in / PatchReleasedSource
redhatundertow-core2026-06-10redhat
redhateap8-wildfly-0:8.1.6-7.GA_redhat_00010.1.el9eap2026-06-10redhat
mavenio.undertow:undertow-parent—ghsa

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 2 ecosystems)
Debian:14(1)
PackageVulnerable rangeFixed inDependents
undertow1.3.11-1 ... 2.3.8-2 (56 versions)——
Maven(1)
PackageVulnerable rangeFixed inDependents
io.undertow:undertow-parent1.0.0.Alpha1 ... 2.3.9.Final (335 versions)——

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 7× in last 7d / 29× 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 214 total refreshes for this CVE.

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

Frequently asked(5)

What is CVE-2026-28368?
CVE-2026-28368 is a critical vulnerability published on March 27, 2026. A flaw was found in Undertow. This vulnerability allows a remote attacker to construct specially crafted requests where header names are parsed differently by Undertow compared to upstream proxies. This discrepancy in header interpretation can be exploited to launch request smuggling attacks,…
When was CVE-2026-28368 disclosed?
CVE-2026-28368 was first published in the National Vulnerability Database on March 27, 2026, with the most recent update on June 29, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-28368 actively exploited?
CVE-2026-28368 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 48.2% of all scored CVEs.
What is the CVSS score of CVE-2026-28368?
CVE-2026-28368 has a CVSS v3 base score of 9.1 (NVD).
How do I remediate CVE-2026-28368?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-28368, 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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