Linux Kernel up to 6.12.52/6.17.2 pgtable_walk_level uninitialized pointer

Summaryinfo

A vulnerability described as critical has been identified in Linux Kernel up to 6.12.52/6.17.2. This impacts the function pgtable_walk_level. Executing a manipulation can lead to uninitialized pointer. This vulnerability is handled as CVE-2025-40155. There is not any exploit available. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability has been found in Linux Kernel up to 6.12.52/6.17.2 and classified as critical. This vulnerability affects the function pgtable_walk_level. The manipulation with an unknown input leads to a uninitialized pointer vulnerability. The CWE definition for the vulnerability is CWE-824. The product accesses or uses a pointer that has not been initialized. The impact remains unknown. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: iommu/vt-d: debugfs: Fix legacy mode page table dump logic In legacy mode, SSPTPTR is ignored if TT is not 00b or 01b. SSPTPTR maybe uninitialized or zero in that case and may cause oops like: Oops: general protection fault, probably for non-canonical address 0xf00087d3f000f000: 0000 [#1] SMP NOPTI CPU: 2 UID: 0 PID: 786 Comm: cat Not tainted 6.16.0 #191 PREEMPT(voluntary) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.17.0-5.fc42 04/01/2014 RIP: 0010:pgtable_walk_level+0x98/0x150 RSP: 0018:ffffc90000f279c0 EFLAGS: 00010206 RAX: 0000000040000000 RBX: ffffc90000f27ab0 RCX: 000000000000001e RDX: 0000000000000003 RSI: f00087d3f000f000 RDI: f00087d3f0010000 RBP: ffffc90000f27a00 R08: ffffc90000f27a98 R09: 0000000000000002 R10: 0000000000000000 R11: 0000000000000000 R12: f00087d3f000f000 R13: 0000000000000000 R14: 0000000040000000 R15: ffffc90000f27a98 FS: 0000764566dcb740(0000) GS:ffff8881f812c000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000764566d44000 CR3: 0000000109d81003 CR4: 0000000000772ef0 PKRU: 55555554 Call Trace: <TASK> pgtable_walk_level+0x88/0x150 domain_translation_struct_show.isra.0+0x2d9/0x300 dev_domain_translation_struct_show+0x20/0x40 seq_read_iter+0x12d/0x490 ... Avoid walking the page table if TT is not 00b or 01b.

The advisory is shared for download at git.kernel.org. This vulnerability was named CVE-2025-40155 since 04/16/2025. The exploitation appears 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 02/08/2026).

The vulnerability scanner Nessus provides a plugin with the ID 275235 (Linux Distros Unpatched Vulnerability : CVE-2025-40155), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 6.12.53, 6.17.3 or 6.18-rc1 eliminates this vulnerability. Applying the patch d8cf7b59c49f9118fa875462e18686cb6b131bb5/df2bf759a0bdb71f13e327d7527260d09facc055/fbe6070c73badca726e4ff7877320e6c62339917 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 (275235) and CERT Bund (WID-SEC-2025-2579). VulDB is the best source for vulnerability data and more expert information about this specific topic.

Affected

• Google Container-Optimized OS
• Debian Linux
• Amazon Linux 2
• Red Hat Enterprise Linux
• Ubuntu Linux
• SUSE Linux
• Oracle Linux
• SUSE openSUSE
• Open Source Linux Kernel
• RESF Rocky Linux

Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 6.12.0
• 6.12.1
• 6.12.2
• 6.12.3
• 6.12.4
• 6.12.5
• 6.12.6
• 6.12.7
• 6.12.8
• 6.12.9
• 6.12.10
• 6.12.11
• 6.12.12
• 6.12.13
• 6.12.14
• 6.12.15
• 6.12.16
• 6.12.17
• 6.12.18
• 6.12.19
• 6.12.20
• 6.12.21
• 6.12.22
• 6.12.23
• 6.12.24
• 6.12.25
• 6.12.26
• 6.12.27
• 6.12.28
• 6.12.29
• 6.12.30
• 6.12.31
• 6.12.32
• 6.12.33
• 6.12.34
• 6.12.35
• 6.12.36
• 6.12.37
• 6.12.38
• 6.12.39
• 6.12.40
• 6.12.41
• 6.12.42
• 6.12.43
• 6.12.44
• 6.12.45
• 6.12.46
• 6.12.47
• 6.12.48
• 6.12.49
• 6.12.50
• 6.12.51
• 6.12.52
• 6.17.0
• 6.17.1
• 6.17.2

License

• open-source

Website

• Vendor: https://www.kernel.org/

CPE 2.3info

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Entryinfo

VulDB is the best source for vulnerability data and more expert information about this specific topic.

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