CVE-2026-28367

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
9.1
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 1%CVSS: 9.1Exploit: NoneExposed: 0

A fix is available — apply it.

A flaw was found in Undertow. A remote attacker can exploit this vulnerability by sending \r\r\r as a header block terminator. This can be used for request smuggling with certain proxy servers, such as older versions of Apache Traffic Server and Google Cloud Classic Application Load Balancer, potentially leading to unauthorized access or manipulation of web requests.

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
49.5%
KEV
Not listed

Published

March 27, 2026

Last Modified

June 29, 2026

Advisory Details (2)

Auto-updated Jun 7, 2026
Patch available. Sources: redhat.
redhat

2443260 – (CVE-2026-28367) CVE-2026-28367 undertow: Undertow: Request smuggling via `\r\r\r` as a header block terminator

https://bugzilla.redhat.com/show_bug.cgi?id=2443260
redhat Patch Available

cve-details

https://access.redhat.com/security/cve/CVE-2026-28367

Vendor Advisories for CVE-2026-28367(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

(1 across 1 ecosystem)
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 14× in last 7d / 48× 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 124 total refreshes for this CVE.

  1. 2026-07-23 03:08 UTCEG score recompute▲ 0.40
  2. 2026-07-22 14:08 UTCEPSS rescore
  3. 2026-07-22 14:08 UTCEPSS rescore
  4. 2026-07-21 15:24 UTCEPSS rescore
  5. 2026-07-21 15:24 UTCEPSS rescore
  6. 2026-07-20 17:08 UTCEPSS rescore
  7. 2026-07-20 17:08 UTCEPSS rescore
  8. 2026-07-19 14:31 UTCEPSS rescore
  9. 2026-07-19 14:31 UTCEPSS rescore
  10. 2026-07-19 02:29 UTCEPSS rescore
  11. 2026-07-18 10:04 UTCEPSS rescore
  12. 2026-07-18 10:04 UTCEPSS rescore
  13. 2026-07-16 17:03 UTCEPSS rescore
  14. 2026-07-16 17:03 UTCEPSS rescore
  15. 2026-07-15 16:57 UTCEPSS rescore
  16. 2026-07-15 16:57 UTCEPSS rescore
  17. 2026-07-15 02:00 UTCEPSS rescore
  18. 2026-07-15 02:00 UTCEPSS rescore
  19. 2026-07-13 22:30 UTCEPSS rescore
  20. 2026-07-13 06:13 UTCEPSS rescore
  21. 2026-07-13 06:13 UTCEPSS rescore
  22. 2026-07-12 05:46 UTCEPSS rescore
  23. 2026-07-11 08:27 UTCEPSS rescore
  24. 2026-07-09 19:10 UTCEPSS rescore
  25. 2026-07-08 15:15 UTCEPSS rescore
Show 75 more
  1. 2026-07-07 13:46 UTCEPSS rescore
  2. 2026-07-06 16:27 UTCEPSS rescore
  3. 2026-07-06 16:27 UTCEPSS rescore
  4. 2026-07-06 02:23 UTCEPSS rescore
  5. 2026-07-06 02:23 UTCEPSS rescore
  6. 2026-07-05 02:30 UTCEPSS rescore
  7. 2026-07-04 06:31 UTCEPSS rescore
  8. 2026-07-01 15:06 UTCEPSS rescore
  9. 2026-06-30 23:22 UTCEPSS rescore
  10. 2026-06-30 23:22 UTCEPSS rescore
  11. 2026-06-29 12:04 UTCNVD updateCVSS v3 → 9.1 · severity → CRITICAL
  12. 2026-06-29 10:17 UTCMITRE cvelistV5CVSS v3 → 8.7 · severity → HIGH
  13. 2026-06-28 14:07 UTCEPSS rescore
  14. 2026-06-28 14:07 UTCEPSS rescore
  15. 2026-06-28 04:56 UTCEPSS rescore
  16. 2026-06-28 04:56 UTCEPSS rescore
  17. 2026-06-27 03:08 UTCEPSS rescore
  18. 2026-06-25 13:49 UTCEPSS rescore
  19. 2026-06-25 13:49 UTCEPSS rescore
  20. 2026-06-24 14:05 UTCEPSS rescore
  21. 2026-06-24 14:05 UTCEPSS rescore
  22. 2026-06-23 21:33 UTCEPSS rescore
  23. 2026-06-23 21:32 UTCEPSS rescore
  24. 2026-06-22 14:25 UTCEPSS rescore
  25. 2026-06-22 14:25 UTCEPSS rescore
  26. 2026-06-21 14:56 UTCEPSS rescore
  27. 2026-06-21 14:56 UTCEPSS rescore
  28. 2026-06-21 01:59 UTCEPSS rescore
  29. 2026-06-21 01:59 UTCEPSS rescore
  30. 2026-06-19 19:25 UTCEPSS rescore
  31. 2026-06-19 19:25 UTCEPSS rescore
  32. 2026-06-18 17:52 UTCEPSS rescore
  33. 2026-06-17 17:53 UTCEPSS rescore
  34. 2026-06-17 17:53 UTCEPSS rescore
  35. 2026-06-16 17:52 UTCEPSS rescore
  36. 2026-06-15 17:48 UTCEPSS rescore
  37. 2026-06-14 23:18 UTCEPSS rescore
  38. 2026-06-13 23:00 UTCEPSS rescore
  39. 2026-06-12 23:12 UTCEPSS rescore
  40. 2026-06-12 23:12 UTCEPSS rescore
  41. 2026-06-11 23:01 UTCVendor advisory
  42. 2026-06-11 23:01 UTCGHSA enrichment
  43. 2026-06-11 14:00 UTCEPSS rescore
  44. 2026-06-10 22:59 UTCNVD updateCVSS v3 → 9.1 · severity → CRITICAL
  45. 2026-06-10 22:18 UTCEPSS rescore
  46. 2026-06-10 22:18 UTCEPSS rescore
  47. 2026-06-10 14:57 UTCGHSA enrichment
  48. 2026-06-10 13:22 UTCEPSS rescore
  49. 2026-06-10 03:11 UTCGHSA enrichment
  50. 2026-06-09 15:25 UTCGHSA enrichment
  51. 2026-06-08 14:17 UTCEPSS rescore
  52. 2026-06-08 14:17 UTCEPSS rescore
  53. 2026-06-08 13:15 UTCGHSA enrichment
  54. 2026-06-08 00:50 UTCGHSA enrichment
  55. 2026-06-07 15:25 UTCEPSS rescore
  56. 2026-06-07 15:25 UTCEPSS rescore
  57. 2026-06-07 15:25 UTCEPSS rescore
  58. 2026-06-07 11:55 UTCGHSA enrichment
  59. 2026-06-06 13:47 UTCEPSS rescore
  60. 2026-06-06 13:47 UTCEPSS rescore
  61. 2026-06-05 22:47 UTCEPSS rescore
  62. 2026-06-05 22:47 UTCEPSS rescore
  63. 2026-06-05 06:10 UTCEPSS rescore
  64. 2026-06-05 06:10 UTCEPSS rescore
  65. 2026-06-04 13:12 UTCEPSS rescore
  66. 2026-06-04 13:12 UTCEPSS rescore
  67. 2026-06-02 20:13 UTCEPSS rescore
  68. 2026-06-02 20:13 UTCEPSS rescore
  69. 2026-06-01 13:51 UTCEPSS rescore
  70. 2026-06-01 13:51 UTCEPSS rescore
  71. 2026-05-31 22:30 UTCEPSS rescore
  72. 2026-05-31 22:30 UTCEPSS rescore
  73. 2026-05-31 00:16 UTCEPSS rescore
  74. 2026-05-31 00:16 UTCEPSS rescore
  75. 2026-05-29 13:44 UTCEPSS rescore

Frequently asked(5)

What is CVE-2026-28367?
CVE-2026-28367 is a critical vulnerability published on March 27, 2026. A flaw was found in Undertow. A remote attacker can exploit this vulnerability by sending \r\r\r as a header block terminator. This can be used for request smuggling with certain proxy servers, such as older versions of Apache Traffic Server and Google Cloud Classic Application Load Balancer,…
When was CVE-2026-28367 disclosed?
CVE-2026-28367 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-2026-28367 actively exploited?
CVE-2026-28367 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 49.5% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-28367?
CVE-2026-28367 has a CVSS v3 base score of 9.1 (NVD).
How do I remediate CVE-2026-28367?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-28367, 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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