CVE-2026-90006 is a vulnerability in Linux Kernel
Published on September 16, 2026
samples/damon/mtier: handle damon_stop() failure
In the Linux kernel, the following vulnerability has been resolved:
samples/damon/mtier: handle damon_stop() failure
damon_sample_mtier_stop() assumes its damon_stop() call will always
successfully stops the two DAMON contexts. Hence it deallocates the two
DAMON contexts after the damon_stop() call. However, if a given context
is already stopped, damon_stop() fails and returns an error while letting
the DAMON contexts that have not yet stopped keep running. This kind of
unexpected early DAMON context stops could happen due to memory allocation
failures in kdamond_fn(). Because damon_sample_mtier_stop() just
deallocates all DAMON contexts with damon_target and damon_region objects
that are linked to the contexts, the execution of the unstopped DAMON
context (kdamond) ends up using the memory that freed (use-after-free).
Fix the issue by separating the damon_stop() to be invoked per context.
Note that DAMON_SYSFS also allows multiple DAMON contexts execution. But,
it calls damon_stop() for each context one by one. Hence this issue is
only in mtier.
For the long term, it would be better to refactor damon_stop() to always
ensure stopping all contexts regardless of the failures in the middle.
Make this fix in the current way, though, to keep it simple and easy to
backport. I will do the refactoring later.
The issue was discovered [1] by Sashiko.
Products Associated with CVE-2026-90006
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Affected Versions
Linux:- Version 82a08bde3cf7bbbe90de57baa181bebf676582c7 and below 3c07c57b894116ae26f01b84c68e68b538ada7ed is affected.
- Version 82a08bde3cf7bbbe90de57baa181bebf676582c7 and below 215f9a7e4f1dcfc05ebcdc5c1ad0ea0dcb47bd09 is affected.
- Version 82a08bde3cf7bbbe90de57baa181bebf676582c7 and below 9dc5b6d66fd51b103eff21ed0df3e292f489ebc0 is affected.
- Version 6.16 is affected.
- Before 6.16 is unaffected.
- Version 6.18.51, <= 6.18.* is unaffected.
- Version 7.2.5, <= 7.2.* is unaffected.
- Version 7.3-rc1, <= * is unaffected.