CVE Catalog

CVE-2025-40270

HighCVSS 7.8
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.12%

2th percentile - higher than 2% of all known CVEs

Summary

In the Linux kernel, the VMA readahead mechanism for swap has a potential Use-After-Free (UAF) vulnerability. During swap device switching, a freed memory reference may occur when VMA readahead tries to read swap entries from another device without proper reference.

Risk Assessment

Risk of system crash or potential code execution due to a race condition between swapoff and swapin. An attacker could exploit this to destabilize the system.

Recommendation

Apply the Linux kernel patch that adds swap device reference checking before read. Update the system to a kernel version containing the fix.

Other vulnerabilities in Linux kernel

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Original NVD description (English source)

In the Linux kernel, the following vulnerability has been resolved: mm, swap: fix potential UAF issue for VMA readahead Since commit 78524b05f1a3 ("mm, swap: avoid redundant swap device pinning"), the common helper for allocating and preparing a folio in the swap cache layer no longer tries to get a swap device reference internally, because all callers of __read_swap_cache_async are already holding a swap entry reference. The repeated swap device pinning isn't needed on the same swap device. Caller of VMA readahead is also holding a reference to the target entry's swap device, but VMA readahead walks the page table, so it might encounter swap entries from other devices, and call __read_swap_cache_async on another device without holding a reference to it. So it is possible to cause a UAF when swapoff of device A raced with swapin on device B, and VMA readahead tries to read swap entries from device A. It's not easy to trigger, but in theory, it could cause real issues. Make VMA readahead try to get the device reference first if the swap device is a different one from the target entry.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS