CVE-2026-59903

HIGHNVD 7.57.5—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 7.5 under NVD CVSS v3. EPSS exploit probability: 0.2% (14th percentile of EPSS-scored CVEs). 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: 0.2%CVSS: 7.5Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

Netty is an asynchronous, event-driven network application framework. Prior to 4.1.137.Final and 4.2.17.Final, io.netty.handler.codec.http.cors.CorsHandler setVaryHeader replaces application Vary headers such as Authorization or Cookie with Origin, allowing a caching proxy or CDN to reuse authenticated responses across users and disclose sensitive information. This issue is fixed in versions 4.1.137.Final and 4.2.17.Final.

CVSS v3
7.5
EG Score
7.5HIGHmedium confidence
EG Risk
34
EG Risk 34/100CISA SSVC

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%
Automatability0% × 15%
CISA SSVC: Track at every mission impact level.
Action: A fix is available. Apply it within your standard update timelines.
EPSS PROB
0.2%
EPSS %ILE
14th
KEV
Not listed

CISA SSVCTrack at every mission impact level.

A fix is available. Apply it within your standard update timelines.

Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

August 17, 2026

Last Modified

September 23, 2026

Advisory Details (5)

Auto-updated Aug 17, 2026
Patch available. Sources: github, github_pr, github_release.
github_release Patch Available

netty-4.2.17.Final

Patch available: netty/netty netty-4.2.17.Final

https://github.com/netty/netty/releases/tag/netty-4.2.17.Final
github_release Patch Available

netty-4.1.137.Final

Patch available: netty/netty netty-4.1.137.Final

https://github.com/netty/netty/releases/tag/netty-4.1.137.Final
github_pr Patch Available

Merge changes from forks (#17213)

Patch available: netty/netty netty-4.1.137.Final (PR #17217 merged 2026-08-06)

https://github.com/netty/netty/pull/17217
github_pr Patch Available

Merge changes from forks

Patch available: netty/netty netty-4.2.17.Final (PR #17213 merged 2026-08-04)

https://github.com/netty/netty/pull/17213
githubMentions a patch (unverified)

Cache Poisoning and Information Disclosure via CORS Vary Header Overwrite · Advisory · netty/netty · GitHub

https://github.com/netty/netty/security/advisories/GHSA-8c42-7qj2-3j46

Vendor Advisories for CVE-2026-59903(2)

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

Affected Packages

(4 across 4 ecosystems)
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
netty1:4.1.48-10 ... 1:4.1.48-9 (12 versions)
  • every version on: no fix on record
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
netty1:4.1.48-10 ... 1:4.1.48-16 (8 versions)
  • every version on: no fix on record
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
netty1:4.1.48-10 ... 1:4.1.48-16 (7 versions)
  • every version on: no fix on record
—
Maven(1)
PackageVulnerable rangeFix by version rangeDependents
io.netty:netty-codec-http4.0.0.Alpha1 ... 4.1.99.Final (230 versions)
  • 4.2.0.Final up to 4.2.17.Final: fixed in 4.2.17.Final
  • every version up to 4.1.137.Final: fixed in 4.1.137.Final
—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 11× in last 7d / 52× 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.

  1. 2026-10-09 20:07 UTCEPSS rescore
  2. 2026-10-08 17:13 UTCEPSS rescore
  3. 2026-10-07 23:48 UTCEPSS rescore
  4. 2026-10-06 21:44 UTCEG score recompute
  5. 2026-10-06 15:18 UTCEPSS rescore
  6. 2026-10-06 09:02 UTCEG score recompute
  7. 2026-10-05 17:43 UTCEPSS rescore
  8. 2026-10-05 06:38 UTCEG score recompute
  9. 2026-10-04 23:22 UTCEPSS rescore
  10. 2026-10-03 17:47 UTCEG score recompute
  11. 2026-10-03 14:26 UTCEPSS rescore
  12. 2026-10-03 02:34 UTCEG score recompute
  13. 2026-10-02 17:56 UTCEPSS rescore
  14. 2026-10-02 01:34 UTCEG score recompute
  15. 2026-10-01 19:50 UTCEPSS rescore
  16. 2026-09-30 20:52 UTCEG score recompute
  17. 2026-09-30 15:03 UTCEPSS rescore
  18. 2026-09-30 09:59 UTCEG score recompute
  19. 2026-09-29 15:22 UTCEPSS rescore
  20. 2026-09-28 21:59 UTCEG score recompute
  21. 2026-09-28 13:51 UTCEPSS rescore
  22. 2026-09-27 18:54 UTCEG score recompute
  23. 2026-09-27 13:48 UTCEPSS rescore
  24. 2026-09-27 08:05 UTCEG score recompute
  25. 2026-09-26 15:59 UTCEPSS rescore
Show 70 more
  1. 2026-09-25 02:01 UTCEG score recompute
  2. 2026-09-24 14:04 UTCEPSS rescore
  3. 2026-09-24 02:26 UTCEG score recompute
  4. 2026-09-23 17:54 UTCEPSS rescore
  5. 2026-09-23 15:38 UTCEG score recompute▲ 1.00
  6. 2026-09-23 15:36 UTCNVD updateCVSS v3 → 7.5 · severity → HIGH
  7. 2026-09-22 23:47 UTCEG score recompute
  8. 2026-09-21 23:44 UTCEG score recompute
  9. 2026-09-20 23:53 UTCEG score recompute
  10. 2026-09-20 20:16 UTCEPSS rescore
  11. 2026-09-20 00:01 UTCEG score recompute
  12. 2026-09-19 00:10 UTCEG score recompute
  13. 2026-09-18 19:28 UTCEPSS rescore
  14. 2026-09-18 00:18 UTCEG score recompute
  15. 2026-09-17 19:31 UTCEPSS rescore
  16. 2026-09-16 23:07 UTCEG score recompute
  17. 2026-09-16 14:08 UTCEPSS rescore
  18. 2026-09-16 05:15 UTCEPSS rescore
  19. 2026-09-15 21:27 UTCEG score recompute
  20. 2026-09-15 03:11 UTCEPSS rescore
  21. 2026-09-13 20:32 UTCEG score recompute
  22. 2026-09-13 16:47 UTCEPSS rescore
  23. 2026-09-12 20:41 UTCEG score recompute
  24. 2026-09-11 20:51 UTCEG score recompute
  25. 2026-09-11 14:53 UTCEPSS rescore
  26. 2026-09-10 20:59 UTCEG score recompute
  27. 2026-09-10 09:35 UTCEPSS rescore
  28. 2026-09-09 05:35 UTCEG score recompute
  29. 2026-09-08 22:01 UTCEPSS rescore
  30. 2026-09-08 05:44 UTCEG score recompute
  31. 2026-09-07 16:01 UTCEPSS rescore
  32. 2026-09-07 05:32 UTCEG score recompute
  33. 2026-09-06 13:47 UTCEPSS rescore
  34. 2026-09-06 05:28 UTCEG score recompute
  35. 2026-09-05 05:38 UTCEG score recompute
  36. 2026-09-04 05:48 UTCEG score recompute
  37. 2026-09-04 05:07 UTCEPSS rescore
  38. 2026-09-03 05:49 UTCEG score recompute
  39. 2026-09-02 14:12 UTCEPSS rescore
  40. 2026-09-02 05:00 UTCEG score recompute
  41. 2026-09-01 13:54 UTCEPSS rescore
  42. 2026-09-01 05:06 UTCEG score recompute
  43. 2026-09-01 04:40 UTCEPSS rescore
  44. 2026-08-31 05:13 UTCEG score recompute
  45. 2026-08-30 19:17 UTCEPSS rescore
  46. 2026-08-30 05:23 UTCEG score recompute
  47. 2026-08-30 01:22 UTCEPSS rescore
  48. 2026-08-29 05:29 UTCEG score recompute
  49. 2026-08-28 21:42 UTCEPSS rescore
  50. 2026-08-27 19:25 UTCEG score recompute
  51. 2026-08-27 14:25 UTCEPSS rescore
  52. 2026-08-26 18:18 UTCEG score recompute
  53. 2026-08-26 14:46 UTCEPSS rescore
  54. 2026-08-25 18:21 UTCEG score recompute
  55. 2026-08-25 13:49 UTCEPSS rescore
  56. 2026-08-24 18:30 UTCEG score recompute
  57. 2026-08-23 18:40 UTCEG score recompute
  58. 2026-08-23 00:19 UTCEPSS rescore
  59. 2026-08-22 18:50 UTCEG score recompute
  60. 2026-08-21 23:49 UTCEPSS rescore
  61. 2026-08-21 18:59 UTCEG score recompute
  62. 2026-08-20 22:55 UTCEPSS rescore
  63. 2026-08-19 19:16 UTCEG score recompute
  64. 2026-08-19 17:04 UTCEPSS rescore
  65. 2026-08-18 19:18 UTCEG score recompute
  66. 2026-08-18 13:48 UTCEPSS rescore
  67. 2026-08-17 19:27 UTCEG score recompute
  68. 2026-08-17 18:21 UTCEG score recompute
  69. 2026-08-17 18:10 UTCEG score recompute
  70. 2026-08-17 18:09 UTCMITRE cvelistV5first tracked

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Frequently asked(5)

What is CVE-2026-59903?
CVE-2026-59903 is a high vulnerability published on August 17, 2026. Netty is an asynchronous, event-driven network application framework. Prior to 4.1.137.Final and 4.2.17.Final, io.netty.handler.codec.http.cors.CorsHandler setVaryHeader replaces application Vary headers such as Authorization or Cookie with Origin, allowing a caching proxy or CDN to reuse…
When was CVE-2026-59903 disclosed?
CVE-2026-59903 was first published on August 17, 2026, with the most recent update on September 23, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-59903 actively exploited?
CVE-2026-59903 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.2% probability of exploitation in the next 30 days (14th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-59903?
CVE-2026-59903 has a CVSS v3 base score of 7.5 (NVD).
How do I remediate CVE-2026-59903?
A fix for CVE-2026-59903 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-59903 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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