CVE-2026-90209 Affecting linux-6.12 package, versions <6.12.111-1~deb12u1
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-DEBIAN12-LINUX612-20507240
- published5 Oct 2026
- disclosed17 Sept 2026
Introduced: 17 Sep 2026
NewCVE-2026-90209 (opens in a new tab)How to fix?
Upgrade Debian:12 linux-6.12 to version 6.12.111-1~deb12u1 or higher.
NVD Description
Note: Versions mentioned in the description apply only to the upstream linux-6.12 package and not the linux-6.12 package as distributed by Debian.
See How to fix? for Debian:12 relevant fixed versions and status.
In the Linux kernel, the following vulnerability has been resolved:
s390/debug: Fix deadlock during unregister
Unregistering an s390dbf debug area while one of the associated debugfs files is being written to can cause a deadlock:
$ echo >.../vmur/level $ rmmod vmur
debugfs write debugfs_file_get() debug_unregister() mutex_lock(debug_mutex) debugfs_remove() wait for debugfs_file_put() debug_file_ops.write() debug_input() mutex_lock(debug_mutex) ==> DEADLOCK
Fix this by splitting debug_unregister() into an s390dbf and debugfs part, and running only the s390dbf part with debug_mutex locked.
References
- https://security-tracker.debian.org/tracker/CVE-2026-90209
- https://git.kernel.org/stable/c/183f8f6d64bb0510070c856b9927618c53014a7b
- https://git.kernel.org/stable/c/445c31ac638fd1af203d79bdf25fc0cb3149fbbc
- https://git.kernel.org/stable/c/45bb341d1b73eb293e0dd43d9b72bbc8b615d0ba
- https://git.kernel.org/stable/c/54e1259b75d6402a1d0cfb822b9bb2c507e53dab
- https://git.kernel.org/stable/c/5d83f3faa3fb7f23f298cfd40382611999de5d1d
- https://git.kernel.org/stable/c/a08b70ed2d1ec907353a72f15163b8e34ff4b2f8
- https://git.kernel.org/stable/c/a214c3dacc779b2afcb0ac9c8001e45ee4ffb2ed