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 48% 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: 0.9%CVSS: 9.1Exploit: None knownExposed services: Not assessed

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
9.1CRITICALmedium confidence
EG Risk
41
EG Risk 41/100

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%
EPSS PROB
0.9%
EPSS %ILE
58th
KEV
Not listed

Published

March 27, 2026

Last Modified

September 21, 2026

Advisory Details (4)

Auto-updated Sep 16, 2026
Patch available. Sources: redhat.
redhatMentions a patch (unverified)

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

https://bugzilla.redhat.com/show_bug.cgi?id=2443261
redhatMentions a patch (unverified)

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
redhatMentions a patch (unverified)
https://access.redhat.com/errata/RHSA-2026:25126
redhatMentions a patch (unverified)
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 / EcosystemFix (by version range) / 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 rangeFix by version rangeDependents
undertow1.3.11-1 ... 2.3.8-2 (56 versions)
  • every version on: no fix on record
—
Maven(1)
PackageVulnerable rangeFix by version rangeDependents
io.undertow:undertow-parent1.0.0.Alpha1 ... 2.3.9.Final (336 versions)
  • every version through 2.3.23.Final: no fix on record
—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 6× in last 7d / 27× 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 232 total refreshes for this CVE.

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

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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 on March 27, 2026, with the most recent update on September 21, 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 0.9% probability of exploitation in the next 30 days (58th percentile of EPSS-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?
A fix for CVE-2026-28368 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-28368 are linked in the Vendor Advisories panel on this page.

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