CVE-2025-37778Network attack vector

Kernel memory corruption via stale session pointer

Published May 1, 2025 · Updated Aug 5, 2026

Use-after-free in the ksmbd session setup path in Linux allows remote attackers to corrupt kernel memory through Kerberos authentication. krb_authenticate frees sess->user without clearing it, and smb2_sess_setup later dereferences that stale pointer if ksmbd_krb5_authenticate returns without replacing it. The gate is network access to an enabled ksmbd server during Kerberos session setup; the stale access can corrupt kernel memory and interrupt the host.

CVSS severity9.8
Critical
EPSS probability1.09%
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 the ksmbd session setup path in Linux allows remote attackers to corrupt kernel memory through Kerberos authentication. krb_authenticate frees sess->user without clearing it, and smb2_sess_setup later dereferences that stale pointer if ksmbd_krb5_authenticate returns without replacing it. The gate is network access to an enabled ksmbd server during Kerberos session setup; the stale access can corrupt kernel memory and interrupt the host.

The record

CVE
CVE-2025-37778
Published
May 1, 2025
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 1, 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 <1db2451de23e98bc864c6a6e52aa0d82c91cb325
  2. Affected versionversion=0626e6641f6b467447c81dd7678a69c66f7746cf <1e440d5b25b7efccb3defe542a73c51005799a5f
  3. Affected versionversion=0626e6641f6b467447c81dd7678a69c66f7746cf <6e30c0e10210c714f3d4453dc258d4abcc70364e
  4. Affected versionversion=0626e6641f6b467447c81dd7678a69c66f7746cf <b61f04d5d73c53d183019bafe22fb700a739bac5
  5. Affected versionversion=0626e6641f6b467447c81dd7678a69c66f7746cf <d5b554bc8d554ed6ddf443d3db2fad9f665cec10
  6. Affected versionversion=0626e6641f6b467447c81dd7678a69c66f7746cf <e83e39a5f6a01a81411a4558a59a10f87aa88dd6
  7. Affected versionversion=5.15

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=0626e6641f6b467447c81dd7678a69c66f7746cf <1db2451de23e98bc864c6a6e52aa0d82c91cb325; version=0626e6641f6b467447c81dd7678a69c66f7746cf <1e440d5b25b7efccb3defe542a73c51005799a5f; version=0626e6641f6b467447c81dd7678a69c66f7746cf <6e30c0e10210c714f3d4453dc258d4abcc70364e; version=0626e6641f6b467447c81dd7678a69c66f7746cf <b61f04d5d73c53d183019bafe22fb700a739bac5; version=0626e6641f6b467447c81dd7678a69c66f7746cf <d5b554bc8d554ed6ddf443d3db2fad9f665cec10; version=0626e6641f6b467447c81dd7678a69c66f7746cf <e83e39a5f6a01a81411a4558a59a10f87aa88dd6; version=5.15

Published CVSS scores

9.8LinuxCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
7.8Canonical UbuntuCVSS:3.1/AV:L/AC:L/PR:L/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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