CVE-2024-56755

Local filesystem-cache hang via missed wake-up

Published Dec 29, 2024 · Updated May 11, 2026

Race condition in Linux netfs/fscache allows local users to hang a filesystem-cache operation indefinitely through concurrent volume lookups. In fscache_create_volume(), a bit is cleared and waiters are awakened as separate operations without the memory barrier needed to expose the cleared state before wake-up. Triggering the flaw requires two lookups for the same cache volume, and the affected lookup can remain blocked indefinitely without disclosing or modifying data.

CVSS severity5.5
Medium
EPSS probability0.21%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Race condition in Linux netfs/fscache allows local users to hang a filesystem-cache operation indefinitely through concurrent volume lookups. In fscache_create_volume(), a bit is cleared and waiters are awakened as separate operations without the memory barrier needed to expose the cleared state before wake-up. Triggering the flaw requires two lookups for the same cache volume, and the affected lookup can remain blocked indefinitely without disclosing or modifying data.

The record

CVE
CVE-2024-56755
Published
Dec 29, 2024
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Dec 29, 2024CVE publishedPublication date reported by the CVE source.
  2. May 11, 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=5.17
  2. Affected versionversion=bfa22da3ed652aa15acd4246fa13a0de6dbe4a59 <22f9400a6f3560629478e0a64247b8fcc811a24d
  3. Affected versionversion=bfa22da3ed652aa15acd4246fa13a0de6dbe4a59 <539fabba965e119b98066fc6ba5257b5eaf4eda2
  4. Affected versionversion=bfa22da3ed652aa15acd4246fa13a0de6dbe4a59 <8beb682cc9a0798a280bbb95e3e41617237090b2
  5. Affected versionversion=bfa22da3ed652aa15acd4246fa13a0de6dbe4a59 <8cc1df3113cb71a0df2c46dd5b102c9e11c8a8c6
  6. Affected versionversion=bfa22da3ed652aa15acd4246fa13a0de6dbe4a59 <ddab02607eed9e415dc62fde421d4329e5345315

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=5.17; version=bfa22da3ed652aa15acd4246fa13a0de6dbe4a59 <22f9400a6f3560629478e0a64247b8fcc811a24d; version=bfa22da3ed652aa15acd4246fa13a0de6dbe4a59 <539fabba965e119b98066fc6ba5257b5eaf4eda2; version=bfa22da3ed652aa15acd4246fa13a0de6dbe4a59 <8beb682cc9a0798a280bbb95e3e41617237090b2; version=bfa22da3ed652aa15acd4246fa13a0de6dbe4a59 <8cc1df3113cb71a0df2c46dd5b102c9e11c8a8c6; version=bfa22da3ed652aa15acd4246fa13a0de6dbe4a59 <ddab02607eed9e415dc62fde421d4329e5345315

Published CVSS scores

5.5Oracle LinuxCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
5.5Amazon LinuxCVSS: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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1499.004Application or System Exploitation

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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