CVE-2026-23331

MEDIUMNVD 5.55.5—
EchelonGraph scoreMEDIUM confidence

Score 5.5 from GitHub Security Advisory published 2026-03-25. NVD baseline CVSS 5.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
5.5EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 5.5Exploit: None knownExposed: 0

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

In the Linux kernel, the following vulnerability has been resolved:

udp: Unhash auto-bound connected sk from 4-tuple hash table when disconnected.

Let's say we bind() an UDP socket to the wildcard address with a non-zero port, connect() it to an address, and disconnect it from the address.

bind() sets SOCK_BINDPORT_LOCK on sk->sk_userlocks (but not SOCK_BINDADDR_LOCK), and connect() calls udp_lib_hash4() to put the socket into the 4-tuple hash table.

Then, __udp_disconnect() calls sk->sk_prot->rehash(sk).

It computes a new hash based on the wildcard address and moves the socket to a new slot in the 4-tuple hash table, leaving a garbage in the chain that no packet hits.

Let's remove such a socket from 4-tuple hash table when disconnected.

Note that udp_sk(sk)->udp_portaddr_hash needs to be udpated after udp_hash4_dec(hslot2) in udp_unhash4().

CVSS v3
5.5
EG Score
5.5(medium)
EG Risk
29(Track)
EG Risk 29/100SSVC: Track

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
Severity55% × 45%
Exploitation0% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
2%
KEV
Not listed

Published

March 25, 2026

Last Modified

June 17, 2026

Advisory Details (3)

Auto-updated Aug 6, 2026
No patch confirmed yet.
generic

udp: Unhash auto-bound connected sk from 4-tuple hash table when disconnected. - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/b955350778b8715e1b7885179979b3a68221c0fb
generic

udp: Unhash auto-bound connected sk from 4-tuple hash table when disconnected. - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/6996a2d2d0a64808c19c98002aeb5d9d1b2df6a4
generic

udp: Unhash auto-bound connected sk from 4-tuple hash table when disconnected. - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/3b8f104880c104151f8c30f2f89df81fb59a286c

Patch Availability(1)

Vendor / EcosystemFixed in / PatchReleasedSource
linuxKernel @ 6.18.17—osv

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

(1 across 1 ecosystem)
Debian:14(1)
PackageVulnerable rangeFixed inDependents
linux6.12.100-1 ... 6.19~rc8-1~exp1 (120 versions)6.19.8-1—

Data Freshness Timeline

(refreshed 4× in last 7d / 24× 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 189 total refreshes for this CVE.

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

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Frequently asked(5)

What is CVE-2026-23331?
CVE-2026-23331 is a medium vulnerability published on March 25, 2026. In the Linux kernel, the following vulnerability has been resolved: udp: Unhash auto-bound connected sk from 4-tuple hash table when disconnected. Let's say we bind() an UDP socket to the wildcard address with a non-zero port, connect() it to an address, and disconnect it from the address. bind()…
When was CVE-2026-23331 disclosed?
CVE-2026-23331 was first published in the National Vulnerability Database on March 25, 2026, with the most recent update on June 17, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-23331 actively exploited?
CVE-2026-23331 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 97.8% of all scored CVEs.
What is the CVSS score of CVE-2026-23331?
CVE-2026-23331 has a CVSS v3 base score of 5.5 (NVD).
How do I remediate CVE-2026-23331?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-23331, 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.

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