CVE-2022-50095
In the Linux kernel, the following vulnerability has been resolved: posix-cpu-timers: Cleanup CPU timers before freeing them during exec Commit 55e8c8eb2c7b ("posix-cpu-timers: Store a reference to a pid not a task") started looking up tasks by PID when…
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.24%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
In the Linux kernel, the following vulnerability has been resolved: posix-cpu-timers: Cleanup CPU timers before freeing them during exec Commit 55e8c8eb2c7b ("posix-cpu-timers: Store a reference to a pid not a task") started looking up tasks by PID when deleting a CPU timer. When a non-leader thread calls execve, it will switch PIDs with the leader process. Then, as it calls exit_itimers, posix_cpu_timer_del cannot find the task because the timer still points out to the old PID. That means that armed timers won't be disarmed, that is, they won't be removed from the timerqueue_list. exit_itimers will still release their memory, and when that list is later processed, it leads to a use-after-free. Clean up the timers from the de-threaded task before freeing them. This prevents a reported use-after-free.
- CVSS 3.1
- 7.8 HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 0.24% probability · 15th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-416
- Affected
- linux/linux kernel
- Source
- 416baaa9-dc9f-4396-8d5f-8c081fb06d67
References
- https://git.kernel.org/stable/c/541840859ace9c2ccebc32fa9e376c7bd3def490Patch
- https://git.kernel.org/stable/c/9e255ed238fc67058df87b0388ad6d4b2ef3a2bdPatch
- https://git.kernel.org/stable/c/b2fc1723eb65abb83e00d5f011de670296af0b28Patch
- https://git.kernel.org/stable/c/e362359ace6f87c201531872486ff295df306d13Patch
- https://git.kernel.org/stable/c/e8cb6e8fd9890780f1bfcf5592889e1b879e779cPatch
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.