CVE-2017-18241

Severity: medium (CVSS 5.5 v3.0)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2018-03-21 · updated 2026-06-17
Weakness: CWE-476

Description

fs/f2fs/segment.c in the Linux kernel before 4.13 allows local users to cause a denial of service (NULL pointer dereference and panic) by using a noflush_merge option that triggers a NULL value for a flush_cmd_control data structure.

Affected products

Canonical Ubuntu Linux: 14.04, 16.04
Debian Linux: 8.0, 9.0
Linux kernel: before 4.13 — fixed in 4.13

How to fix

Upgrade to a fixed version: Linux kernel 4.13. Check the vendor advisory for mitigations.

References

http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=d4fdf8ba0e5808ba9ad6b44337783bd9935e0982
https://github.com/torvalds/linux/commit/d4fdf8ba0e5808ba9ad6b44337783bd9935e0982
https://usn.ubuntu.com/3910-1/
https://usn.ubuntu.com/3910-2/
https://www.debian.org/security/2018/dsa-4187
https://www.debian.org/security/2018/dsa-4188
http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=d4fdf8ba0e5808ba9ad6b44337783bd9935e0982
https://github.com/torvalds/linux/commit/d4fdf8ba0e5808ba9ad6b44337783bd9935e0982
https://usn.ubuntu.com/3910-1/
https://usn.ubuntu.com/3910-2/
https://www.debian.org/security/2018/dsa-4187
https://www.debian.org/security/2018/dsa-4188

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