CVE-2024-56549

Kernel memory corruption via cachefiles lifetime race

Published Dec 27, 2024 · Updated Aug 5, 2026

Use-after-free in Linux cachefiles on-demand mode allows local users to corrupt kernel memory through a cookie-withdrawal race. cachefiles_ondemand_fd_write_iter retains no reference to object->file while cookie withdrawal can call fput() and clear it before __cachefiles_write() or llseek uses it. An unprivileged user with access to an on-demand EROFS/FS-Cache mount can race demand reads against unmount or LRU withdrawal, causing a kernel crash or redirected reads and writes.

CVSS severity7.8
High
EPSS probability0.23%
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 cachefiles on-demand mode allows local users to corrupt kernel memory through a cookie-withdrawal race. cachefiles_ondemand_fd_write_iter retains no reference to object->file while cookie withdrawal can call fput() and clear it before __cachefiles_write() or llseek uses it. An unprivileged user with access to an on-demand EROFS/FS-Cache mount can race demand reads against unmount or LRU withdrawal, causing a kernel crash or redirected reads and writes.

The record

CVE
CVE-2024-56549
Published
Dec 27, 2024
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-476, T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Dec 27, 2024CVE 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=5.19
  2. Affected versionversion=c8383054506c77b814489c09877b5db83fd4abf2 <31ad74b20227ce6b40910ff78b1c604e42975cf1
  3. Affected versionversion=c8383054506c77b814489c09877b5db83fd4abf2 <785408bbafcfa24c9fc5b251f03fd0780ce182bd
  4. Affected versionversion=c8383054506c77b814489c09877b5db83fd4abf2 <9582c7664103c9043e80a78f5c382aa6bdd67418
  5. Affected versionversion=c8383054506c77b814489c09877b5db83fd4abf2 <d6bba3ece960129a553d4b16f1b00c884dc0993a
  6. Affected versionversion=c8383054506c77b814489c09877b5db83fd4abf2 <f98770440c9bc468e2fd878212ec9526dbe08293

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=5.19; version=c8383054506c77b814489c09877b5db83fd4abf2 <31ad74b20227ce6b40910ff78b1c604e42975cf1; version=c8383054506c77b814489c09877b5db83fd4abf2 <785408bbafcfa24c9fc5b251f03fd0780ce182bd; version=c8383054506c77b814489c09877b5db83fd4abf2 <9582c7664103c9043e80a78f5c382aa6bdd67418; version=c8383054506c77b814489c09877b5db83fd4abf2 <d6bba3ece960129a553d4b16f1b00c884dc0993a; version=c8383054506c77b814489c09877b5db83fd4abf2 <f98770440c9bc468e2fd878212ec9526dbe08293

Published CVSS scores

5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
7.8Linux Kernel CNACVSS: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.

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

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

CWE-476NULL Pointer Dereference
T1499.004Application or System Exploitation

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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