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 40% 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
60%
KEV
Not listed

Published

May 13, 2026

Last Modified

August 13, 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(13)

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

Patch Availability(7)

Vendor / EcosystemFixed in / PatchReleasedSource
redhatnetty-codec-http22026-08-12redhat
redhateap7-wildfly-0:7.4.25-2.GA_redhat_00001.1.el7eap2026-08-11redhat
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.

Data Freshness Timeline

(refreshed 11× in last 7d / 84× 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 190 total refreshes for this CVE.

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

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 August 13, 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 40.1% 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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