Use-after-free in Linux kernel - CVE-2026-99203
Published: October 29, 2026
Vulnerability identifier: #VU158378
CSH Severity: Low
CVSS v4: 5.7 [CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-99203
CWE-ID: CWE-416
Exploitation vector: Local access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a local user to cause a denial of service.
The vulnerability exists due to use-after-free in the Linux kernel pipe_fasync() function when concurrent attempts to enable asynchronous notifications on an O_RDWR FIFO encounter a writer-entry allocation failure. A local user can trigger concurrent enables under memory pressure, causing an existing reader registration to be removed while the writer registration remains active, to leave a stale reference that may crash the kernel during a later pipe notification.
Affected software
Linux kernel
Debian Linux
linux (Debian package)
Debian Linux
linux (Debian package)
How to mitigate CVE-2026-99203
Install security update from vendor's repository.
Linux kernel - update to 7.0 rc3
linux (Debian package) - update to 6.12.115-2
linux (Debian package) - update to 6.12.115-2