CVE-2023-52440

HIGHNVD 7.87.8—
EchelonGraph scoreMEDIUM confidence

Score 7.8 from GitHub Security Advisory (severity: HIGH) published 2024-02-21. NVD baseline CVSS 7.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
Trending — 4 sources updated this weekElevated
7.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 22%CVSS: 7.8Exploit: Elevated riskExposed: 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:

ksmbd: fix slub overflow in ksmbd_decode_ntlmssp_auth_blob()

If authblob->SessionKey.Length is bigger than session key size(CIFS_KEY_SIZE), slub overflow can happen in key exchange codes. cifs_arc4_crypt copy to session key array from SessionKey from client.

CVSS v3
7.8
EG Score
7.8(medium)
EG Risk
51(Track)
EG Risk 51/100SSVC: 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
Severity78% × 45%
Exploitation40% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
22%
EPSS %ILE
97%
KEV
Not listed

Published

February 21, 2024

Last Modified

August 5, 2026

Advisory Details (5)

Auto-updated Aug 4, 2026
No patch confirmed yet.
generic

ksmbd: fix slub overflow in ksmbd_decode_ntlmssp_auth_blob() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/ecd7e1c562cb08e41957fcd4b0e404de5ab38e20
generic

ksmbd: fix slub overflow in ksmbd_decode_ntlmssp_auth_blob() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/bd554ed4fdc3d38404a1c43d428432577573e809
generic

ksmbd: fix slub overflow in ksmbd_decode_ntlmssp_auth_blob() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/7f1d6cb0eb6af3a8088dc24b7ddee9a9711538c4
generic

ksmbd: fix slub overflow in ksmbd_decode_ntlmssp_auth_blob() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/4b081ce0d830b684fdf967abc3696d1261387254
generic

ksmbd: fix slub overflow in ksmbd_decode_ntlmssp_auth_blob() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/30fd6521b2fbd9b767e438e31945e5ea3e3a2fba

Patch Availability(1)

Vendor / EcosystemFixed in / PatchReleasedSource
linuxKernel @ 5.15.145—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.

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 14× in last 7d / 45× 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 110 total refreshes for this CVE.

  1. 2026-08-07 16:25 UTCEPSS rescore
  2. 2026-08-06 13:45 UTCEPSS rescore
  3. 2026-08-05 19:15 UTCEPSS rescore
  4. 2026-08-05 19:15 UTCEPSS rescore
  5. 2026-08-05 09:46 UTCEG score recompute▼ 0.10
  6. 2026-08-05 09:46 UTCGHSA enrichment
  7. 2026-08-04 12:25 UTCEG score recompute
  8. 2026-08-04 12:25 UTCGHSA enrichment
  9. 2026-08-04 10:36 UTCEPSS rescore
  10. 2026-08-04 09:55 UTCEG score recompute
  11. 2026-08-04 09:55 UTCGHSA enrichment
  12. 2026-08-02 02:25 UTCEPSS rescore
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  14. 2026-08-01 12:06 UTCOSV refresh
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  24. 2026-07-23 02:29 UTCEG score recompute▲ 0.10
  25. 2026-07-22 23:15 UTCEG score recompute
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  1. 2026-07-22 14:07 UTCEPSS rescore
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  13. 2026-07-14 19:25 UTCOSV refresh
  14. 2026-07-13 22:28 UTCEPSS rescore
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  26. 2026-06-30 23:21 UTCEPSS rescore
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  28. 2026-06-29 14:05 UTCEPSS rescore
  29. 2026-06-28 04:55 UTCEPSS rescore
  30. 2026-06-27 03:07 UTCEPSS rescore
  31. 2026-06-26 20:09 UTCOSV refresh
  32. 2026-06-25 13:48 UTCEPSS rescore
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  47. 2026-06-14 23:16 UTCEPSS rescore
  48. 2026-06-13 22:59 UTCEPSS rescore
  49. 2026-06-13 22:59 UTCEPSS rescore
  50. 2026-06-12 23:11 UTCEPSS rescore
  51. 2026-06-11 13:59 UTCEPSS rescore
  52. 2026-06-10 22:17 UTCEPSS rescore
  53. 2026-06-10 13:21 UTCEPSS rescore
  54. 2026-06-09 05:30 UTCOSV refresh
  55. 2026-06-08 14:16 UTCEPSS rescore
  56. 2026-06-08 14:16 UTCEPSS rescore
  57. 2026-06-07 15:24 UTCEPSS rescore
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  59. 2026-06-06 13:46 UTCEPSS rescore
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  74. 2026-05-29 13:43 UTCEPSS rescore
  75. 2026-05-28 13:44 UTCEPSS rescore

Publicly available exploits

(1 reference)

Working exploit code is in the public domain (1 GitHub PoC). Defenders should treat patch urgency accordingly — public PoCs typically lead to mass-exploitation within 24-72 hours.

  • GitHub PoCBitsByWill/ksmbd-n-day
    First seen Sep 12, 2025

    Authenticated 0-click RCE against Linux 6.1.45 for CVE-2023-52440 and CVE-2023-4130

    Open source ↗

Related CVEs(same product + same CWE)

Frequently asked(5)

What is CVE-2023-52440?
CVE-2023-52440 is a high vulnerability published on February 21, 2024. In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix slub overflow in ksmbddecodentlmsspauthblob() If authblob->SessionKey.Length is bigger than session key size(CIFSKEYSIZE), slub overflow can happen in key exchange codes. cifsarc4crypt copy to session key array from…
When was CVE-2023-52440 disclosed?
CVE-2023-52440 was first published in the National Vulnerability Database on February 21, 2024, with the most recent update on August 5, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2023-52440 actively exploited?
CVE-2023-52440 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 22% probability of exploitation in the next 30 days, which ranks it in the top 2.6% of all scored CVEs.
What is the CVSS score of CVE-2023-52440?
CVE-2023-52440 has a CVSS v3 base score of 7.8 (NVD).
How do I remediate CVE-2023-52440?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2023-52440, 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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