CVE-2017-18257

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: 2018-04-04 · updated 2026-06-17
Weakness: CWE-190

Description

The __get_data_block function in fs/f2fs/data.c in the Linux kernel before 4.11 allows local users to cause a denial of service (integer overflow and loop) via crafted use of the open and fallocate system calls with an FS_IOC_FIEMAP ioctl.

Affected products

Debian Linux: 9.0
Linux kernel: before 4.11 — fixed in 4.11

How to fix

Upgrade to a fixed version: Linux kernel 4.11. Check the vendor advisory for mitigations.

References

http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=b86e33075ed1909d8002745b56ecf73b833db143
https://github.com/torvalds/linux/commit/b86e33075ed1909d8002745b56ecf73b833db143
https://usn.ubuntu.com/3696-1/
https://usn.ubuntu.com/3696-2/
https://www.debian.org/security/2018/dsa-4188
http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=b86e33075ed1909d8002745b56ecf73b833db143
https://github.com/torvalds/linux/commit/b86e33075ed1909d8002745b56ecf73b833db143
https://usn.ubuntu.com/3696-1/
https://usn.ubuntu.com/3696-2/
https://www.debian.org/security/2018/dsa-4188

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