Cloudanix VulnDB

CVE-2026-80697

None

CVSS

—

EPSS

0.2%

Published

Aug 28, 2026

CISA due date

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Cloudanix analysis

Schedule a fix SSVC: Track

A flaw in how the Linux kernel handles certain filesystem operations can cause the whole computer to crash when inspecting file cache usage on specific storage setups.

Exploitation
Local Privilege
Attacker needs
Local User
Complexity
Low
Impact
Denial Of Service
Component
OS kernel
Class
Memory Corruption
Remediation
Patch
Effort
Medium
Patch risk
Low

What it actually does

Null pointer dereference in __do_sys_mincore when erofs backing files for page cache sharing have f_path left as NULL (only f_inode populated), violating assumptions in mincore that require f_path.mnt.

Why it matters to the business

Kernel panic or system crash on Linux hosts using EROFS with page cache sharing, resulting in denial of service and potential operational disruption until the system is restarted.

How an attack unfolds

An attacker invokes the mincore syscall (e.g., via fincore) against files on an affected EROFS filesystem configured for page cache sharing; the call reaches __do_sys_mincore which dereferences the missing f_path.mnt, triggering the oops.

How to fix it

Upgrade the Linux kernel to a version containing the erofs fix that supplies valid disconnected dentries and uses erofs_ishare_mnt together with backing_file_open() instead of leaving f_path empty.

How to confirm the fix worked

Confirm the running kernel contains the erofs f_path fix; test by running mincore against EROFS-backed files with page cache sharing and verify no NULL pointer dereference occurs.

Typical attack path

  1. Locate or mount an EROFS filesystem using page cache sharing
  2. Execute mincore or equivalent file cache inspection on target files
  3. Trigger NULL pointer dereference in kernel mincore handling
  4. Cause kernel oops and system instability or reboot

How to detect it

Search kernel logs and oops reports for __do_sys_mincore NULL pointer dereference combined with erofs or fincore activity; inspect crash dumps for f_path.mnt references in the erofs backing file path.

  • BUG: kernel NULL pointer dereference
  • __do_sys_mincore+0xc0
  • erofs/028
  • fincore

What your security team should do

  • Prioritize kernel updates on systems using EROFS
  • Review EROFS page cache sharing configurations for exposure
  • Monitor kernel logs for mincore-related oops entries
  • Test the fix in representative lab environments before broad rollout

The record

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.

Affected packages

Ecosystem Package Introduced Fixed