Use-after-free in Linux kernel - CVE-2026-98985

Vulnerability details

The vulnerability allows a local privileged user to trigger a use-after-free read that may cause a denial of service.

The vulnerability exists due to use-after-free in path_pivot_root() in fs/namespace.c when reading mount parents before verifying that the mounts belong to the caller's mount namespace. A local privileged user can invoke pivot_root() with a reference to an unmounted mount while its parent is concurrently released to trigger a read of freed memory, potentially causing a denial of service.

The same invalid parent read can also occur through the caller's root set via chroot().

Affected software

How to mitigate CVE-2026-98985

External References

• https://git.kernel.org/stable/c/3c2441e21c3df867e4131e0ff784ecdb3a7a55f8
• https://git.kernel.org/stable/c/3dad2330c89343ba083cf7868779083fd5fbe0fe
• https://git.kernel.org/stable/c/6b7c001eb5857fa09041f47673666060a2e5fc1c
• https://git.kernel.org/stable/c/a56d4f8f8f4c5d9ac339d5c03a9d90eecd3697fc
• https://git.kernel.org/stable/c/e3aba6900483f64e6c9eb328150dd633b7d36c1c

Related Security Bulletins

• Use-after-free in Linux kernel fs
• Debian update for linux