Linux Kernel up to 6.18.3/6.19-rc3 kimage_map_segment allocation of resources

Summaryinfo

A vulnerability marked as critical has been reported in Linux Kernel up to 6.18.3/6.19-rc3. Impacted is the function kimage_map_segment. The manipulation leads to allocation of resources. This vulnerability is listed as CVE-2025-71139. There is no available exploit. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as critical, has been found in Linux Kernel up to 6.18.3/6.19-rc3. This issue affects the function kimage_map_segment. The manipulation with an unknown input leads to a allocation of resources vulnerability. Using CWE to declare the problem leads to CWE-770. The product allocates a reusable resource or group of resources on behalf of an actor without imposing any restrictions on the size or number of resources that can be allocated, in violation of the intended security policy for that actor. The impact remains unknown. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: kernel/kexec: fix IMA when allocation happens in CMA area *** Bug description *** When I tested kexec with the latest kernel, I ran into the following warning: [ 40.712410] ------------[ cut here ]------------ [ 40.712576] WARNING: CPU: 2 PID: 1562 at kernel/kexec_core.c:1001 kimage_map_segment+0x144/0x198 [...] [ 40.816047] Call trace: [ 40.818498] kimage_map_segment+0x144/0x198 (P) [ 40.823221] ima_kexec_post_load+0x58/0xc0 [ 40.827246] __do_sys_kexec_file_load+0x29c/0x368 [...] [ 40.855423] ---[ end trace 0000000000000000 ]--- *** How to reproduce *** This bug is only triggered when the kexec target address is allocated in the CMA area. If no CMA area is reserved in the kernel, use the "cma=" option in the kernel command line to reserve one. *** Root cause *** The commit 07d24902977e ("kexec: enable CMA based contiguous allocation") allocates the kexec target address directly on the CMA area to avoid copying during the jump. In this case, there is no IND_SOURCE for the kexec segment. But the current implementation of kimage_map_segment() assumes that IND_SOURCE pages exist and map them into a contiguous virtual address by vmap(). *** Solution *** If IMA segment is allocated in the CMA area, use its page_address() directly.

The advisory is shared at git.kernel.org. The identification of this vulnerability is CVE-2025-71139 since 01/13/2026. The exploitation is known to be difficult. Technical details are known, but no exploit is available.

The vulnerability scanner Nessus provides a plugin with the ID 284709 (Linux Distros Unpatched Vulnerability : CVE-2025-71139), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 6.18.4 or 6.19-rc4 eliminates this vulnerability. Applying the patch a843e4155c83211c55b1b6cc17eab27a6a2c5b6f/a3785ae5d334bb71d47a593d54c686a03fb9d136 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 (284709) and CERT Bund (WID-SEC-2026-0119). If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Affected

• Open Source Linux Kernel

Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 6.18.0
• 6.18.1
• 6.18.2
• 6.18.3
• 6.19-rc1
• 6.19-rc2
• 6.19-rc3

License

• open-source

Website

• Vendor: https://www.kernel.org/

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