Linux Kernel up to 6.18.6/6.19-rc5 ftrace_process_locs allocation of resources

Summaryinfo

A vulnerability categorized as critical has been discovered in Linux Kernel up to 6.18.6/6.19-rc5. This affects the function ftrace_process_locs. Such manipulation leads to allocation of resources. This vulnerability is traded as CVE-2026-23052. There is no exploit available. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as critical, has been found in Linux Kernel up to 6.18.6/6.19-rc5. Affected by this issue is the function ftrace_process_locs. 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. Impacted is confidentiality, integrity, and availability. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: ftrace: Do not over-allocate ftrace memory The pg_remaining calculation in ftrace_process_locs() assumes that ENTRIES_PER_PAGE multiplied by 2^order equals the actual capacity of the allocated page group. However, ENTRIES_PER_PAGE is PAGE_SIZE / ENTRY_SIZE (integer division). When PAGE_SIZE is not a multiple of ENTRY_SIZE (e.g. 4096 / 24 = 170 with remainder 16), high-order allocations (like 256 pages) have significantly more capacity than 256 * 170. This leads to pg_remaining being underestimated, which in turn makes skip (derived from skipped - pg_remaining) larger than expected, causing the WARN(skip != remaining) to trigger. Extra allocated pages for ftrace: 2 with 654 skipped WARNING: CPU: 0 PID: 0 at kernel/trace/ftrace.c:7295 ftrace_process_locs+0x5bf/0x5e0 A similar problem in ftrace_allocate_records() can result in allocating too many pages. This can trigger the second warning in ftrace_process_locs(). Extra allocated pages for ftrace WARNING: CPU: 0 PID: 0 at kernel/trace/ftrace.c:7276 ftrace_process_locs+0x548/0x580 Use the actual capacity of a page group to determine the number of pages to allocate. Have ftrace_allocate_pages() return the number of allocated pages to avoid having to calculate it. Use the actual page group capacity when validating the number of unused pages due to skipped entries. Drop the definition of ENTRIES_PER_PAGE since it is no longer used.

The advisory is shared for download at git.kernel.org. This vulnerability is handled as CVE-2026-23052 since 01/13/2026. The exploitation is known to be difficult. There are known technical details, but no exploit is available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 04/30/2026).

The vulnerability scanner Nessus provides a plugin with the ID 297964 (Linux Distros Unpatched Vulnerability : CVE-2026-23052), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 6.18.7 or 6.19-rc6 eliminates this vulnerability. Applying the patch 9aef476717994e96dadfb359641c4b82b521aa36/be55257fab181b93af38f8c4b1b3cb453a78d742 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 (297964) and CERT Bund (WID-SEC-2026-0324). Once again VulDB remains the best source for vulnerability data.

Affected

• Debian Linux
• Google Cloud Platform
• Amazon Linux 2
• Red Hat Enterprise Linux
• Ubuntu Linux
• SUSE Linux
• Oracle Linux
• IBM QRadar SIEM
• SUSE openSUSE
• RESF Rocky Linux
• 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
• 6.18.4
• 6.18.5
• 6.18.6
• 6.19-rc1
• 6.19-rc2
• 6.19-rc3
• 6.19-rc4
• 6.19-rc5

License

• open-source

Website

• Vendor: https://www.kernel.org/

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