Linux Kernel up to 7.2.3 mm/page_owner print_page_owner_memcg toctou

Summaryinfo

A vulnerability, which was classified as very critical, was found in Linux Kernel up to 7.2.3. The affected element is the function print_page_owner_memcg of the component mm/page_owner. The manipulation results in toctou. This vulnerability is cataloged as CVE-2026-93216. The attack may be launched remotely. There is no exploit available. You should upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as very critical, was found in Linux Kernel up to 7.2.3. Affected is the function print_page_owner_memcg of the component mm/page_owner. The manipulation with an unknown input leads to a toctou vulnerability. CWE is classifying the issue as CWE-367. The product checks the state of a resource before using that resource, but the resource's state can change between the check and the use in a way that invalidates the results of the check. This can cause the product to perform invalid actions when the resource is in an unexpected state. This is going to have an impact on confidentiality, integrity, and availability. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: mm/page_owner: use memcg_data snapshot to avoid TOCTOU in print_page_owner_memcg() print_page_owner_memcg() reads page->memcg_data via READ_ONCE() at the start to guard against tail pages and NULL data. However, it later re-reads page->memcg_data locklessly in two places: 1: page_memcg_check(page) 2: PageMemcgKmem(page) (via folio_memcg_kmem(), which includes VM_BUG_ON assertions for tail pages and MEMCG_DATA_OBJEXTS) If the page is concurrently freed and reallocated as a THP tail page or slab page between these calls, the VM_BUG_ON assertions can trigger on CONFIG_DEBUG_VM=y builds, crashing the kernel. Fix both TOCTOU issues by using the memcg_data snapshot throughout.

The advisory is shared for download at git.kernel.org. This vulnerability is traded as CVE-2026-93216 since 09/17/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. 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 09/24/2026).

Upgrading to version 7.2.4 or 7.3-rc1 eliminates this vulnerability. Applying the patch 46761406e14381dc35f498c247a87565b87ea2ef/90f095b816e25c6a9e4446d299bac5007fdcb3df is able to eliminate this problem. The best possible mitigation is suggested to be upgrading to the latest version.

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Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 7.2.0
• 7.2.1
• 7.2.2
• 7.2.3

License

• open-source

Website

• Vendor: https://www.kernel.org/

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