CVE-2026-98388: exec: do_close_on_exec() before taking exec_update_lock

Severity: unknown
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-10-14 · updated 2026-10-19

Description

In the Linux kernel, the following vulnerability has been resolved: exec: do_close_on_exec() before taking exec_update_lock do_close_on_exec() currently happens while holding the exec_update_lock, which is used in a lot of places that access process state to synchronize access checks. I recently added another such use of exec_update_lock, causing a regression. do_close_on_exec() can block waiting for a reply from a filesystem. That means a hung filesystem can block codepaths that use exec_update_lock; and it also means that a FUSE filesystem which attempts to inspect the calling process can deadlock. To avoid such problems, move do_close_on_exec() before the exec_update_lock is taken, but after the FD table has been copied if necessary. I have looked through all the calls between the old and new position of the do_close_on_exec() call; there seems to be no file descriptor table access in between.

Affected products

Linux kernel: from 5.10.261 before 5.10.271; from 5.15.212 before 5.15.222; from 6.1.178 before 6.1.189; from 6.6.145 before 6.6.158; from 6.12.97 before 6.12.111; from 6.18.40 before 6.18.53 — fixed in 5.10.271, 5.15.222, 6.1.189, 6.12.111, 6.18.53, 6.6.158

How to fix

Upgrade to a fixed version: Linux kernel 5.10.271, 5.15.222, 6.1.189, 6.12.111. Check the vendor advisory for mitigations.

References

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