CVE-2026-42587

HIGHPre-NVD 7.57.5—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 7.5 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 1.0%, top 39% 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, secondary
Trending — 3 sources updated this weekElevated
7.5EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 1%CVSS: 7.5Exploit: Elevated riskExposed: 0

A fix is available — apply it.

Netty is an asynchronous, event-driven network application framework. Prior to 4.2.13.Final and 4.1.133.Final, HttpContentDecompressor accepts a maxAllocation parameter to limit decompression buffer size and prevent decompression bomb attacks. This limit is correctly enforced for gzip and deflate encodings via ZlibDecoder, but is silently ignored when the content encoding is br (Brotli), zstd, or snappy. An attacker can bypass the configured decompression limit by sending a compressed payload with Content-Encoding: br instead of Content-Encoding: gzip, causing unbounded memory allocation and out-of-memory denial of service. The same vulnerability exists in DelegatingDecompressorFrameListener for HTTP/2 connections. This vulnerability is fixed in 4.2.13.Final and 4.1.133.Final.

CVSS v3
7.5
EG Score
7.5(medium)
EG Risk
65(Attend)
EG Risk 65/100SSVC: Attend

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%
Exploitation40% × 40%
Automatability100% × 15%
Action: Remediate soon — notable exploitation risk.
EPSS PROB
1%
EPSS %ILE
61%
KEV
Not listed

Published

May 13, 2026

Last Modified

September 18, 2026

Advisory Details (1)

Auto-updated May 13, 2026
🔬 Proof of concept available. Patch available. Sources: github.
github Patch Available🟡 PoC Available

HttpContentDecompressor maxAllocation bypass via Content-Encoding: br/zstd/snappy enables decompression bomb DoS · Advisory · netty/netty · GitHub

https://github.com/netty/netty/security/advisories/GHSA-f6hv-jmp6-3vwv

Vendor Advisories for CVE-2026-42587(18)

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

Patch Availability(13)

Vendor / EcosystemFixed in / PatchReleasedSource
redhatnetty-codec-http22026-09-10redhat
redhatnetty-codec-http2026-09-10redhat
redhatrhoai/odh-trustyai-service-rhel9:17881986812026-09-08redhat
redhateap7-wildfly-0:7.4.25-2.GA_redhat_00001.1.el8eap2026-08-11redhat
redhateap7-wildfly-0:7.4.25-2.GA_redhat_00001.1.el9eap2026-08-11redhat
redhateap7-wildfly-0:7.4.25-2.GA_redhat_00001.1.el7eap2026-08-11redhat
redhatio.netty/netty-codec-http:4.1.135.Final-redhat-000012026-08-03redhat
redhateap8-wildfly-0:8.1.7.1-1.GA_redhat_00004.1.el9eap2026-08-03redhat
redhatrhoai/odh-modelmesh-rhel9:17834438162026-07-21redhat
redhatdevspaces/multicluster-redirector-rhel9:17829890272026-07-08redhat
redhatcryostat/jfr-datasource-rhel9:4.2.0-102026-06-22redhat
redhatdevspaces/server-rhel9:17806949942026-06-10redhat
redhatpatch2026-06-10redhat

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

(6 across 5 ecosystems)
Maven(2)
PackageVulnerable rangeFixed inDependents
io.netty:netty-codec-http4.0.0.Alpha1 ... 4.1.99.Final (226 versions)4.1.133.Final—
io.netty:netty-codec-http24.1.0.Beta4 ... 4.1.99.Final (145 versions)4.1.133.Final—
Debian:11(1)
PackageVulnerable rangeFixed inDependents
netty1:4.1.48-10 ... 1:4.1.48-9 (16 versions)——
Debian:12(1)
PackageVulnerable rangeFixed inDependents
netty1:4.1.48-10 ... 1:4.1.48-9 (12 versions)——
Debian:13(1)
PackageVulnerable rangeFixed inDependents
netty1:4.1.48-10 ... 1:4.1.48-16 (8 versions)——
Debian:14(1)
PackageVulnerable rangeFixed inDependents
netty1:4.1.48-10 ... 1:4.1.48-16 (7 versions)——

Weakness Classification(2)

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

Additional Vendor Advisories

(2)

Vendors that published advisories for this CVE beyond the curated set above. Broader coverage but minimal per-row detail — click through for the original advisory.

Data Freshness Timeline

(refreshed 14× in last 7d / 54× 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 234 total refreshes for this CVE.

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

Related CVEs(same vendor + same CWE)

Frequently asked(5)

What is CVE-2026-42587?
CVE-2026-42587 is a high vulnerability published on May 13, 2026. Netty is an asynchronous, event-driven network application framework. Prior to 4.2.13.Final and 4.1.133.Final, HttpContentDecompressor accepts a maxAllocation parameter to limit decompression buffer size and prevent decompression bomb attacks. This limit is correctly enforced for gzip and deflate…
When was CVE-2026-42587 disclosed?
CVE-2026-42587 was first published in the National Vulnerability Database on May 13, 2026, with the most recent update on September 18, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-42587 actively exploited?
CVE-2026-42587 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 39.0% of all scored CVEs.
What is the CVSS score of CVE-2026-42587?
CVE-2026-42587 has a CVSS v3 base score of 7.5 (NVD).
How do I remediate CVE-2026-42587?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-42587, 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-2026-42587

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