CVE-2026-22991 libceph: make free_choose_arg_map() resilient to partial allocation

What is CVE-2026-22991?

CVE-2026-22991 is a high-severity vulnerability in Linux kernel, published on 23 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:

libceph: make free_choose_arg_map() resilient to partial allocation

free_choose_arg_map() may dereference a NULL pointer if its caller fails after a partial allocation.

For example, in decode_choose_args(), if allocation of arg_map->args fails, execution jumps to the fail label and free_choose_arg_map() is called. Since arg_map->size is updated to a non-zero value before memory allocation, free_choose_arg_map() will iterate over arg_map->args and dereference a NULL pointer.

To prevent this potential NULL pointer dereference and make free_choose_arg_map() more resilient, add checks for pointers before iterating.

Weakness: CWE-476

Which versions are affected by CVE-2026-22991?

It affects 1 product.

Products include Linux kernel.

How do I fix CVE-2026-22991?

Apply the vendor's patch.

Is CVE-2026-22991 being exploited?

There is no known exploitation of CVE-2026-22991 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-78470, BELL-CVE-2026-22991, DEBIAN-CVE-2026-22991, GHSA-953j-p37p-r755, ROOT-OS-DEBIAN-11-CVE-2026-22991, ROOT-OS-DEBIAN-12-CVE-2026-22991 and 4 more.