UBUNTU-CVE-2026-46183
In the Linux kernel, the following vulnerability has been resolved: mm/damon/sysfs-schemes: protect path kfree() with damon_sysfs_lock damon_sysfs_quot_goal->path can be read and written by users, via DAMON sysfs 'path' file. It can also be indirectly read, for the parameters {on,off}line committing to DAMON. The reads for parameters committing are protected by damon_sysfs_lock to avoid the sysfs files being destroyed while any of the parameters are being read. But the user-driven direct reads and writes are not protected by any lock, while the write is deallocating the path-pointing buffer. As a result, the readers could read the already freed buffer (user-after-free). Note that the user-reads don't race when the same open file is used by the writer, due to kernfs's open file locking. Nonetheless, doing the reads and writes with separate open files would be common. Fix it by protecting both the user-direct reads and writes with damon_sysfs_lock.
02 / AFFECTED SOFTWARE
Affected packages
11 explicit affected versions
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51 explicit affected versions
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37 explicit affected versions
13 explicit affected versions
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11 explicit affected versions
26 explicit affected versions
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23 explicit affected versions
10 explicit affected versions
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7 explicit affected versions
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26 explicit affected versions
11 explicit affected versions
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16 explicit affected versions
10 explicit affected versions
18 explicit affected versions
12 explicit affected versions
27 explicit affected versions
3 explicit affected versions
3 explicit affected versions
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6 explicit affected versions
10 explicit affected versions
7 explicit affected versions
13 explicit affected versions
7 explicit affected versions
8 explicit affected versions
10 explicit affected versions
12 explicit affected versions
9 explicit affected versions
9 explicit affected versions
44 explicit affected versions
16 explicit affected versions
3 explicit affected versions
13 explicit affected versions
45 explicit affected versions
37 explicit affected versions
14 explicit affected versions
38 explicit affected versions
7 explicit affected versions
14 explicit affected versions
4 explicit affected versions
78 explicit affected versions
11 explicit affected versions
1 explicit affected versions
6 explicit affected versions
03 / CONNECTIONS
Connected vulnerabilities
04 / EVIDENCE
Source records
In the Linux kernel, the following vulnerability has been resolved: mm/damon/sysfs-schemes: protect path kfree() with damon_sysfs_lock damon_sysfs_quot_goal->path can be read and written by users, via DAMON sysfs 'path' file. It can also be indirectly read, for the parameters {on,off}line committing to DAMON. The reads for parameters committing are protected by damon_sysfs_lock to avoid the sysfs files being destroyed while any of the parameters are being read. But the user-driven direct reads and writes are not protected by any lock, while the write is deallocating the path-pointing buffer. As a result, the readers could read the already freed buffer (user-after-free). Note that the user-reads don't race when the same open file is used by the writer, due to kernfs's open file locking. Nonetheless, doing the reads and writes with separate open files would be common. Fix it by protecting both the user-direct reads and writes with damon_sysfs_lock.
05 / REFERENCES
Further evidence
- https://git.kernel.org/linus/cf3b71421ca00807328c6d9cd242f9de3b77a4bf
- https://git.kernel.org/stable/c/a34ca3e33da4b924c66bcca3729bf68ec5936910
- https://git.kernel.org/stable/c/cf3b71421ca00807328c6d9cd242f9de3b77a4bf
- https://ubuntu.com/security/CVE-2026-46183
- https://ubuntu.com/security/notices/USN-8566-1
- https://ubuntu.com/security/notices/USN-8568-1
- https://ubuntu.com/security/notices/USN-8569-1
- https://ubuntu.com/security/notices/USN-8593-1
- https://ubuntu.com/security/notices/USN-8603-1
- https://ubuntu.com/security/notices/USN-8618-1
- https://www.cve.org/CVERecord?id=CVE-2026-46183