CVE-2026-56818

MEDIUMPre-NVD 6.56.5—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 6.5 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.3%, top 79% 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
6.5EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 6.5Exploit: Elevated riskExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

Netty is an asynchronous, event-driven network application framework. Prior to 4.1.136.Final and 4.2.16.Final, the RedisArrayAggregator Redis codec clears retained partial aggregate state when the maxNestedArrayDepth limit is exceeded, but it does not clear the same state when the sibling maxElements limit is exceeded. A peer can start a valid RESP array, send a bulk string child, then send a nested array header longer than the configured maxElements. Netty throws a decoder exception in decodeRedisArrayHeader, but the existing partial aggregate remains retained in the handler. If the application leaves the channel alive after the exception, later messages are still consumed into the pre-error aggregate, allowing an unauthenticated peer to keep attacker-controlled aggregate state alive across a security-limit exception and pin retained pooled buffers. This issue is fixed in versions 4.1.136.Final and 4.2.16.Final.

CVSS v3
6.5
EG Score
6.5(medium)
EG Risk
60(Attend)
EG Risk 60/100SSVC: 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
Severity65% × 45%
Exploitation40% × 40%
Automatability100% × 15%
Action: Remediate soon — notable exploitation risk.
EPSS PROB
0%
EPSS %ILE
21%
KEV
Not listed

Published

August 7, 2026

Last Modified

September 10, 2026

Advisory Details (4)

Auto-updated Aug 7, 2026
🔬 Proof of concept available. Patch available. Sources: github_commit, github_pr, github.
github Patch Available🟡 PoC Available

RedisArrayAggregator max-elements failure leaves retained partial aggregate state · Advisory · netty/netty · GitHub

https://github.com/netty/netty/security/advisories/GHSA-p9jm-q85p-7mcp
github_pr Patch Available

Merge branches from forks (#17063)

Patch available: netty/netty netty-4.1.136.Final (PR #17065 merged 2026-07-08)

https://github.com/netty/netty/pull/17065
github_commit Patch Available

commit bb2ff68a1fb7 (netty/netty)

Patch available: netty/netty netty-4.1.136.Final (contains commit bb2ff68a1fb7)

https://github.com/netty/netty/commit/bb2ff68a1fb71cb4b0eb9a9e17b66c52aff680c6
github_commit Patch Available

commit 5b68c61f37aa (netty/netty)

Patch available: netty/netty netty-4.2.16.Final (contains commit 5b68c61f37aa)

https://github.com/netty/netty/commit/5b68c61f37aa4a3045cba624cbea239655c9003b

Vendor Advisories for CVE-2026-56818(1)

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

Affected Packages

(5 across 5 ecosystems)
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)——
Maven(1)
PackageVulnerable rangeFixed inDependents
io.netty:netty-codec-redis4.2.0.Final ... 4.2.9.Final (16 versions)4.2.16.Final—

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 13× in last 7d / 51× 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. 2026-09-19 06:40 UTCEG score recompute
  2. 2026-09-18 19:28 UTCEPSS rescore
  3. 2026-09-18 08:10 UTCEG score recompute
  4. 2026-09-17 19:31 UTCEPSS rescore
  5. 2026-09-17 10:12 UTCEG score recompute
  6. 2026-09-16 14:08 UTCEPSS rescore
  7. 2026-09-16 12:13 UTCEG score recompute
  8. 2026-09-16 05:15 UTCEPSS rescore
  9. 2026-09-15 14:15 UTCEG score recompute
  10. 2026-09-15 03:11 UTCEPSS rescore
  11. 2026-09-14 13:13 UTCEG score recompute
  12. 2026-09-13 16:47 UTCEPSS rescore
  13. 2026-09-12 17:14 UTCEG score recompute
  14. 2026-09-11 19:15 UTCEG score recompute
  15. 2026-09-11 14:53 UTCEPSS rescore
  16. 2026-09-10 20:59 UTCEG score recompute
  17. 2026-09-10 09:35 UTCEPSS rescore
  18. 2026-09-09 06:00 UTCEG score recompute
  19. 2026-09-08 22:01 UTCEPSS rescore
  20. 2026-09-07 20:25 UTCEG score recompute
  21. 2026-09-07 16:01 UTCEPSS rescore
  22. 2026-09-06 22:27 UTCEG score recompute
  23. 2026-09-06 13:47 UTCEPSS rescore
  24. 2026-09-06 00:26 UTCEG score recompute
  25. 2026-09-05 02:22 UTCEG score recompute
Show 52 more
  1. 2026-09-04 05:07 UTCEPSS rescore
  2. 2026-09-03 06:00 UTCEG score recompute
  3. 2026-09-02 14:12 UTCEPSS rescore
  4. 2026-09-02 06:47 UTCEG score recompute
  5. 2026-09-01 13:54 UTCEPSS rescore
  6. 2026-09-01 07:10 UTCEG score recompute
  7. 2026-09-01 04:40 UTCEPSS rescore
  8. 2026-08-31 06:36 UTCEG score recompute
  9. 2026-08-30 19:17 UTCEPSS rescore
  10. 2026-08-30 08:24 UTCEG score recompute
  11. 2026-08-30 01:22 UTCEPSS rescore
  12. 2026-08-29 10:23 UTCEG score recompute
  13. 2026-08-28 21:42 UTCEPSS rescore
  14. 2026-08-28 11:53 UTCEG score recompute
  15. 2026-08-27 14:25 UTCEPSS rescore
  16. 2026-08-27 11:32 UTCEG score recompute
  17. 2026-08-26 14:46 UTCEPSS rescore
  18. 2026-08-25 15:33 UTCEG score recompute
  19. 2026-08-25 13:49 UTCEPSS rescore
  20. 2026-08-24 17:33 UTCEG score recompute
  21. 2026-08-23 18:05 UTCEG score recompute
  22. 2026-08-23 00:19 UTCEPSS rescore
  23. 2026-08-22 20:07 UTCEG score recompute
  24. 2026-08-21 23:49 UTCEPSS rescore
  25. 2026-08-21 00:07 UTCEG score recompute
  26. 2026-08-20 22:55 UTCEPSS rescore
  27. 2026-08-20 02:08 UTCEG score recompute
  28. 2026-08-19 17:04 UTCEPSS rescore
  29. 2026-08-19 04:09 UTCEG score recompute
  30. 2026-08-18 13:48 UTCEPSS rescore
  31. 2026-08-18 06:08 UTCEG score recompute
  32. 2026-08-17 13:47 UTCEPSS rescore
  33. 2026-08-17 08:09 UTCEG score recompute
  34. 2026-08-16 14:56 UTCEPSS rescore
  35. 2026-08-16 10:11 UTCEG score recompute
  36. 2026-08-16 02:14 UTCEPSS rescore
  37. 2026-08-15 12:13 UTCEG score recompute
  38. 2026-08-15 01:30 UTCEPSS rescore
  39. 2026-08-14 14:14 UTCEG score recompute
  40. 2026-08-13 22:00 UTCEPSS rescore
  41. 2026-08-12 18:17 UTCEG score recompute
  42. 2026-08-12 13:51 UTCEPSS rescore
  43. 2026-08-11 20:17 UTCEG score recompute
  44. 2026-08-11 00:00 UTCEPSS rescore
  45. 2026-08-10 00:20 UTCEG score recompute
  46. 2026-08-09 13:46 UTCEPSS rescore
  47. 2026-08-09 02:22 UTCEG score recompute
  48. 2026-08-08 16:37 UTCEPSS rescore
  49. 2026-08-08 04:24 UTCEG score recompute
  50. 2026-08-08 03:27 UTCEG score recompute
  51. 2026-08-07 18:26 UTCEG score recompute
  52. 2026-08-07 17:27 UTCEG score recompute

Frequently asked(5)

What is CVE-2026-56818?
CVE-2026-56818 is a medium vulnerability published on August 7, 2026. Netty is an asynchronous, event-driven network application framework. Prior to 4.1.136.Final and 4.2.16.Final, the RedisArrayAggregator Redis codec clears retained partial aggregate state when the maxNestedArrayDepth limit is exceeded, but it does not clear the same state when the sibling…
When was CVE-2026-56818 disclosed?
CVE-2026-56818 was first published in the National Vulnerability Database on August 7, 2026, with the most recent update on September 10, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-56818 actively exploited?
CVE-2026-56818 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 78.9% of all scored CVEs.
What is the CVSS score of CVE-2026-56818?
CVE-2026-56818 has a CVSS v3 base score of 6.5 (NVD).
How do I remediate CVE-2026-56818?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-56818, 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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