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
Elevated
7.5EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 1.0%CVSS: 7.5Exploit: Elevated riskExposed services: Not assessed

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
7.5HIGHmedium confidence
EG Risk
65
EG Risk 65/100

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
Severity75% × 45%
Exploitation40% × 40%
Automatability100% × 15%
EPSS PROB
1.0%
EPSS %ILE
63rd
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.
githubMentions a patch (unverified)🟡 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(20)

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 / EcosystemFix (by version range) / 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 rangeFix by version rangeDependents
io.netty:netty-codec-http4.0.0.Alpha1 ... 4.1.99.Final (226 versions)
  • 4.2.0.Alpha1 up to 4.2.13.Final: fixed in 4.2.13.Final
  • every version up to 4.1.133.Final: fixed in 4.1.133.Final
—
io.netty:netty-codec-http24.1.0.Beta4 ... 4.1.99.Final (145 versions)
  • 4.2.0.Alpha1 up to 4.2.13.Final: fixed in 4.2.13.Final
  • every version up to 4.1.133.Final: fixed in 4.1.133.Final
—
Debian:11(1)
PackageVulnerable rangeFix by version rangeDependents
netty1:4.1.48-10 ... 1:4.1.48-9 (16 versions)
  • every version on: no fix on record
—
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
—

Weakness Classification(2)

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

Additional Vendor Advisories

(6)

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 8× in last 7d / 35× 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 248 total refreshes for this CVE.

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

Related CVEs(same product + 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 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 1.0% probability of exploitation in the next 30 days (63rd percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-42587?
CVE-2026-42587 has a CVSS base score of 7.5 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-42587?
A fix for CVE-2026-42587 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-42587 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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