CVE-2025-37924Network attack vector

Pre-authentication memory corruption via session setup race

Published May 20, 2025 · Updated Aug 5, 2026

Use-after-free in Linux kernel ksmbd 5.15 and later affected branches allows remote attackers to corrupt memory during Kerberos authentication. During concurrent SESSION_SETUP handling, one thread frees sess->user while another dereferences it before the pointer is cleared. Two unauthenticated connections to the same session can control the pre-authentication race, exposing kernel memory to corruption.

CVSS severity9.8
Critical
EPSS probability20.74%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in Linux kernel ksmbd 5.15 and later affected branches allows remote attackers to corrupt memory during Kerberos authentication. During concurrent SESSION_SETUP handling, one thread frees sess->user while another dereferences it before the pointer is cleared. Two unauthenticated connections to the same session can control the pre-authentication race, exposing kernel memory to corruption.

The record

CVE
CVE-2025-37924
Published
May 20, 2025
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1210
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 20, 2025CVE publishedPublication date reported by the CVE source.
  2. Aug 5, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0626e6641f6b467447c81dd7678a69c66f7746cf <28c756738af44a404a91b77830d017bb0c525890
  2. Affected versionversion=0626e6641f6b467447c81dd7678a69c66f7746cf <b447463562238428503cfba1c913261047772f90
  3. Affected versionversion=0626e6641f6b467447c81dd7678a69c66f7746cf <e18c616718018dfc440e4a2d2b94e28fe91b1861
  4. Affected versionversion=0626e6641f6b467447c81dd7678a69c66f7746cf <e34a33d5d7e87399af0a138bb32f6a3e95dd83d2
  5. Affected versionversion=0626e6641f6b467447c81dd7678a69c66f7746cf <e86e9134e1d1c90a960dd57f59ce574d27b9a124
  6. Affected versionversion=5.15

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=0626e6641f6b467447c81dd7678a69c66f7746cf <28c756738af44a404a91b77830d017bb0c525890; version=0626e6641f6b467447c81dd7678a69c66f7746cf <b447463562238428503cfba1c913261047772f90; version=0626e6641f6b467447c81dd7678a69c66f7746cf <e18c616718018dfc440e4a2d2b94e28fe91b1861; version=0626e6641f6b467447c81dd7678a69c66f7746cf <e34a33d5d7e87399af0a138bb32f6a3e95dd83d2; version=0626e6641f6b467447c81dd7678a69c66f7746cf <e86e9134e1d1c90a960dd57f59ce574d27b9a124; version=5.15

Published CVSS scores

9.8Linux Kernel CVE teamCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1210Exploitation of Remote Services

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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