CVE-2025-71072 shmem: fix recovery on rename failures

What is CVE-2025-71072?

CVE-2025-71072 is a high-severity denial of service vulnerability in Linux kernel, published on 13 Jan 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

In the Linux kernel, the following vulnerability has been resolved:

shmem: fix recovery on rename failures

maple_tree insertions can fail if we are seriously short on memory; simple_offset_rename() does not recover well if it runs into that. The same goes for simple_offset_rename_exchange().

Moreover, shmem_whiteout() expects that if it succeeds, the caller will progress to d_move(), i.e. that shmem_rename2() won't fail past the successful call of shmem_whiteout().

Not hard to fix, fortunately - mtree_store() can't fail if the index we are trying to store into is already present in the tree as a singleton.

For simple_offset_rename_exchange() that's enough - we just need to be careful about the order of operations.

For simple_offset_rename() solution is to preinsert the target into the tree for new_dir; the rest can be done without any potentially failing operations.

That preinsertion has to be done in shmem_rename2() rather than in simple_offset_rename() itself - otherwise we'd need to deal with the possibility of failure after successful shmem_whiteout().

Which versions are affected by CVE-2025-71072?

It affects 1 product.

Products include Linux kernel.

How do I fix CVE-2025-71072?

Apply the vendor's patch.

Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.

Is CVE-2025-71072 being exploited?

There is no known exploitation of CVE-2025-71072 in the wild and no public exploit code.

Other vulnerabilities in Linux kernel

• CVE-2026-53266 Linux Kernel Out-of-Bounds Write Exploited High 8.8
• CVE-2013-6282 Linux Kernel Improper Input Validation Exploited High 8.8
• CVE-2022-0185 Linux Kernel Heap-Based Buffer Overflow Exploited High 8.4
• CVE-2013-2094 Linux Kernel Privilege Escalation Exploited High 8.4
• CVE-2026-53362 Linux Kernel Unspecified Exploited High 7.8

All Linux kernel vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as AZL-74420, BELL-CVE-2025-71072, DEBIAN-CVE-2025-71072, GHSA-2j2j-fmxq-39xm, ROOT-OS-UBUNTU-2404-CVE-2025-71072, UBUNTU-CVE-2025-71072.