Linux Kernel up to 6.11.10/6.12.1 cachefiles anon_fd null pointer dereference

Summaryinfo

A vulnerability marked as critical has been reported in Linux Kernel up to 6.11.10/6.12.1. Impacted is the function anon_fd of the component cachefiles. Performing a manipulation results in null pointer dereference. This vulnerability was named CVE-2024-56549. There is no available exploit. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability classified as critical has been found in Linux Kernel up to 6.11.10/6.12.1. This affects the function anon_fd of the component cachefiles. The manipulation with an unknown input leads to a null pointer dereference vulnerability. CWE is classifying the issue as CWE-476. A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit. This is going to have an impact on availability. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: cachefiles: Fix NULL pointer dereference in object->file At present, the object->file has the NULL pointer dereference problem in ondemand-mode. The root cause is that the allocated fd and object->file lifetime are inconsistent, and the user-space invocation to anon_fd uses object->file. Following is the process that triggers the issue: [write fd] [umount] cachefiles_ondemand_fd_write_iter fscache_cookie_state_machine cachefiles_withdraw_cookie if (!file) return -ENOBUFS cachefiles_clean_up_object cachefiles_unmark_inode_in_use fput(object->file) object->file = NULL // file NULL pointer dereference! __cachefiles_write(..., file, ...) Fix this issue by add an additional reference count to the object->file before write/llseek, and decrement after it finished.

It is possible to read the advisory at git.kernel.org. This vulnerability is uniquely identified as CVE-2024-56549 since 12/27/2024. Technical details of the vulnerability are known, but there is no available exploit.

The vulnerability scanner Nessus provides a plugin with the ID 214250 (SUSE SLES15 / openSUSE 15 Security Update : kernel (SUSE-SU-2025:0117-1)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 6.11.11 or 6.12.2 eliminates this vulnerability. Applying the patch f98770440c9bc468e2fd878212ec9526dbe08293/9582c7664103c9043e80a78f5c382aa6bdd67418/31ad74b20227ce6b40910ff78b1c604e42975cf1 is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the databases at Tenable (214250), EUVD (EUVD-2024-53197) and CERT Bund (WID-SEC-2024-3762). Be aware that VulDB is the high quality source for vulnerability data.

Affected

• Debian Linux
• Amazon Linux 2
• Red Hat Enterprise Linux
• Ubuntu Linux
• SUSE Linux
• Oracle Linux
• RESF Rocky Linux
• Dell NetWorker
• Dell Avamar
• Red Hat OpenShift
• IBM QRadar SIEM
• Dell PowerProtect Data Domain
• Open Source Linux Kernel
• IBM DataPower Gateway
• Dell Secure Connect Gateway

Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 6.11.0
• 6.11.1
• 6.11.2
• 6.11.3
• 6.11.4
• 6.11.5
• 6.11.6
• 6.11.7
• 6.11.8
• 6.11.9
• 6.11.10
• 6.12.0
• 6.12.1

License

• open-source

Website

• Vendor: https://www.kernel.org/

CPE 2.3info

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CPE 2.2info

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Entryinfo

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