Public proof of conceptFix available

CVE-2023-52440

Q: Is CVE-2023-52440 actively exploited?

Active exploitation of CVE-2023-52440 has not been confirmed. Its EPSS score was 21.9% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

Q: What is the CVSS score for CVE-2023-52440?

CVE-2023-52440 has a CVSS v3 base score of 7.8 (HIGH severity), with vector string CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

A public proof of concept exists; no exploitation attested.

Published2024-02-21
Fixed in6.5.2 · 6.4.15 · 6.1.52
WeaknessCWE-119

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

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.

Timeline

dates in UTC

2024-02-2108:15CVE publishedNVD
2026-10-2319:23First public proof of conceptPoC-in-GitHub
2026-10-2319:23EPSS crossed 10 %FIRST EPSS

Observed activity

isMalicious corpus · updated 2026-10-23 18:48 UTC

Indicators tagged with this CVE, per day0 indicators over 7 days

Block these indicators

Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2023-52440?format=txt
CSV export: https://api.ismalicious.com/edl/cve/CVE-2023-52440?format=csv
TAXII collection of exploited CVEs
The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD

Linux linux kernel

Branch	Affected	Fixed in	Source
6.5	≥ 6.5.0, < 6.5.2	6.5.2	NVD
6.x	≥ 6.2.0, < 6.4.15	6.4.15	NVD
6.1	≥ 5.17.0, < 6.1.52	6.1.52	NVD

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Fix

Update Linux linux kernel to 6.5.2 · 6.4.15 · 6.1.52

Advisories and patches

Detection

read 2026-10-23 19:23 UTC

Nuclei template: none so far
Exploit-DB: no entry
Proof-of-concept repositories: 1 repository, unverifiedBitsByWill/ksmbd-n-day

Sources

CISA-ADPSSVC decisionnone2024-09-10
OpenCVESSVC decisionnone—
CNACVSS 3.19.8read 2026-10-23
NVDCVSS 3.17.8read 2026-10-23
NVDweakness (CWE)CWE-119read 2026-10-23
FIRST EPSSEPSS score21.9 %read 2026-10-23
PoC-in-GitHubproof of concept1read 2026-10-23

Technical details

CVSS v3 Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Published: 2024-02-21
Last Modified: 2026-08-15
NVD status: Modified

Frequently asked questions

What is CVE-2023-52440?

Is CVE-2023-52440 actively exploited?

Active exploitation of CVE-2023-52440 has not been confirmed. Its EPSS score was 21.9% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2023-52440?

CVE-2023-52440 has a CVSS v3 base score of 7.8 (HIGH severity), with vector string CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

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