Linux Kernel up to 7.1.7 erofs backing_file_open null pointer dereference

Summaryinfo

A vulnerability was found in Linux Kernel up to 7.1.7. It has been rated as problematic. This affects the function backing_file_open of the component erofs. Performing a manipulation results in null pointer dereference. This vulnerability is known as CVE-2026-80697. Attacking locally is a requirement. No exploit is available.

Detailsinfo

A vulnerability classified as problematic has been found in Linux Kernel up to 7.1.7. This affects the function backing_file_open of the component erofs. 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 confidentiality, integrity, and availability. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: erofs: ensure valid f_path for page cache sharing Previously, backing files for page cache sharing were set up with f_path left as NULL (only f_inode was valid). It worked, but a recent mincore fix relies on f_path.mnt and crashes (found by "erofs/028" on 7.2-rc4): BUG: kernel NULL pointer dereference, address: 0000000000000018 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 0 P4D 0 Oops: Oops: 0000 [#1] SMP PTI CPU: 3 UID: 0 PID: 675528 Comm: fincore Not tainted 7.2.0-rc4-00002-g[]-dirty #1 PREEMPT(lazy) Hardware name: Red Hat KVM, BIOS 1.16.0-4.al8 04/01/2014 RIP: 0010:__do_sys_mincore+0xc0/0x2c0 ... Specify valid paths using valid disconnected dentries together with erofs_ishare_mnt instead of leaving f_path empty, so they are more like real backing files in a pseudo filesystem and standard backing_file_open() can be used directly.

The advisory is shared at git.kernel.org. This vulnerability is uniquely identified as CVE-2026-80697 since 08/26/2026. The exploitability is told to be easy. An attack has to be approached locally. Technical details are known, but no exploit is available.

Upgrading to version 7.1.8 eliminates this vulnerability. Applying the patch 3879657c4ffd81b9a42cf575fc6cb60201032587/96b2dbbe58a1ea5df8d29c2fe24b5f04715f4443 is able to eliminate this problem.

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Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 7.1.0
• 7.1.1
• 7.1.2
• 7.1.3
• 7.1.4
• 7.1.5
• 7.1.6
• 7.1.7

License

• open-source

Website

• Vendor: https://www.kernel.org/

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Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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