CVE-2026-97556Hinoki check available

System crash via leaked CIFS file reference

Published Sep 25, 2026 · Updated Sep 25, 2026

A reference leak in the Linux kernel CIFS client allows attackers to crash the system during a later multiuser-share unmount. When cifs_sb_tlink() fails, cifs_oplock_break() exits without passing the queued file reference to _cifsFileInfo_put(). Reachability requires a CIFS mount using -o multiuser, a cifs_sb_tlink() failure during an oplock break, and a later unmount.

CVSS severityUnavailable
Unscored
EPSS probability0.21%
Next 30 days · Oct 19, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

A reference leak in the Linux kernel CIFS client allows attackers to crash the system during a later multiuser-share unmount. When cifs_sb_tlink() fails, cifs_oplock_break() exits without passing the queued file reference to _cifsFileInfo_put(). Reachability requires a CIFS mount using -o multiuser, a cifs_sb_tlink() failure during an oplock break, and a later unmount.

The record

CVE
CVE-2026-97556
Published
Sep 25, 2026
Updated
Sep 25, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
Unavailable
Attack vector
Unavailable
Privileges
Unavailable

Timeline

How it unfolded

  1. Sep 25, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 25, 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=5.15.128 <5.16
  2. Affected versionversion=5ee28bcfbaacf289eb25c662a2862542ea6ce6a7
  3. Affected versionversion=6.1.47 <6.2
  4. Affected versionversion=6.4.12 <6.5
  5. Affected versionversion=6.5
  6. Affected versionversion=6b67a6d2e50634fe127e656147c81915955e9f5e
  7. Affected versionversion=b99f490ea87ebcca3a429fd8837067feb56a4c7c
  8. Affected versionversion=e8f5f849ffce24490eb9449e98312b66c0dba76f <1d1b0f1d812a4011a57bc6c70492c34a2e46c6dd
  9. Affected versionversion=e8f5f849ffce24490eb9449e98312b66c0dba76f <23b26f4408ac3f35a482d2e5cf6fc865d4201b71
  10. Affected versionversion=e8f5f849ffce24490eb9449e98312b66c0dba76f <9ec991e148368e3207e98134c509a625097f7693
  11. Affected versionversion=e8f5f849ffce24490eb9449e98312b66c0dba76f <dd03fd658ea59821505e0e643b6b7cbdf51c4e1d

What conditions does exploitation require?

Attack vectorUnavailable in this record.
Required privilegesUnavailable in this record.

What is affected?

The Linux Kernel Organization · Linuxversion=5.15.128 <5.16; version=5ee28bcfbaacf289eb25c662a2862542ea6ce6a7; version=6.1.47 <6.2; version=6.4.12 <6.5; version=6.5; version=6b67a6d2e50634fe127e656147c81915955e9f5e; version=b99f490ea87ebcca3a429fd8837067feb56a4c7c; version=e8f5f849ffce24490eb9449e98312b66c0dba76f <1d1b0f1d812a4011a57bc6c70492c34a2e46c6dd; version=e8f5f849ffce24490eb9449e98312b66c0dba76f <23b26f4408ac3f35a482d2e5cf6fc865d4201b71; version=e8f5f849ffce24490eb9449e98312b66c0dba76f <9ec991e148368e3207e98134c509a625097f7693; version=e8f5f849ffce24490eb9449e98312b66c0dba76f <dd03fd658ea59821505e0e643b6b7cbdf51c4e1d

Published CVSS scores

No CVSS assessment is available in this record.

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.

Activity data is delayed. The latest report is Sep 28, 2026.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 22, 2026Sep 28, 2026
Latest reporting daySep 28, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
VectorUnavailable
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

No sourced classifications are available.

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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