CVE-2025-21660

Service interruption via stale path-buffer reuse

Published Jan 21, 2025 · Updated May 23, 2026

Path-handling error in the Linux ksmbd SMB server allows local users to interrupt service through a failed multi-entry path lookup. On an error before the final entry, ksmbd_vfs_kern_path_locked returns without restoring the modified path buffer, which later supplies a filename for creation. Reachability requires local low-privileged access and an active ksmbd server; the published assessment limits the consequence to service interruption.

CVSS severity5.5
Medium
EPSS probability0.20%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Path-handling error in the Linux ksmbd SMB server allows local users to interrupt service through a failed multi-entry path lookup. On an error before the final entry, ksmbd_vfs_kern_path_locked returns without restoring the modified path buffer, which later supplies a filename for creation. Reachability requires local low-privileged access and an active ksmbd server; the published assessment limits the consequence to service interruption.

The record

CVE
CVE-2025-21660
Published
Jan 21, 2025
Updated
May 23, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jan 21, 2025CVE publishedPublication date reported by the CVE source.
  2. May 23, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=6.10.13 <6.11
  2. Affected versionversion=6.1.113 <6.1.125
  3. Affected versionversion=6.11.2 <6.12
  4. Affected versionversion=6.12
  5. Affected versionversion=6.6.54 <6.6.72
  6. Affected versionversion=6ab95e27b77730de3fa2d601db3764490c5eede2 <65b31b9d992c0fb0685c51a0cf09993832734fc4
  7. Affected versionversion=c1e27b70e79050530c671b9dab688386c86f039a
  8. Affected versionversion=c5a709f08d40b1a082e44ffcde1aea4d2822ddd5 <2ac538e40278a2c0c051cca81bcaafc547d61372
  9. Affected versionversion=c5a709f08d40b1a082e44ffcde1aea4d2822ddd5 <51669f4af5f7959565b48e55691ba92fabf5c587
  10. Affected versionversion=d1b2d2a9c912fc7b788985fbaf944e80f4b3f2af <13e41c58c74baa71f34c0830eaa3c29d53a6e964
  11. Affected versionversion=d205cb1a13b37b2660df70a972dedc8c4ba1c2e8

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=6.10.13 <6.11; version=6.1.113 <6.1.125; version=6.11.2 <6.12; version=6.12; version=6.6.54 <6.6.72; version=6ab95e27b77730de3fa2d601db3764490c5eede2 <65b31b9d992c0fb0685c51a0cf09993832734fc4; version=c1e27b70e79050530c671b9dab688386c86f039a; version=c5a709f08d40b1a082e44ffcde1aea4d2822ddd5 <2ac538e40278a2c0c051cca81bcaafc547d61372; version=c5a709f08d40b1a082e44ffcde1aea4d2822ddd5 <51669f4af5f7959565b48e55691ba92fabf5c587; version=d1b2d2a9c912fc7b788985fbaf944e80f4b3f2af <13e41c58c74baa71f34c0830eaa3c29d53a6e964; version=d205cb1a13b37b2660df70a972dedc8c4ba1c2e8

Published CVSS scores

5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/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)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1499Endpoint Denial of Service

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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