CVE-2025-68239: binfmt_misc: restore write access before closing files opened by open_exec()

Severity: unknown
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-12-16 · updated 2026-10-15

Description

In the Linux kernel, the following vulnerability has been resolved: binfmt_misc: restore write access before closing files opened by open_exec() bm_register_write() opens an executable file using open_exec(), which internally calls do_open_execat() and denies write access on the file to avoid modification while it is being executed. However, when an error occurs, bm_register_write() closes the file using filp_close() directly. This does not restore the write permission, which may cause subsequent write operations on the same file to fail. Fix this by calling exe_file_allow_write_access() before filp_close() to restore the write permission properly.

Affected products

Linux kernel: from 4.9.262 before 4.10; from 4.14.226 before 4.15; from 4.19.181 before 4.20; from 5.4.106 before 5.5; from 5.10.24 before 5.11; from 5.11.7 before 5.12 — fixed in 4.10, 4.15, 4.20, 5.11, 5.12, 5.5

How to fix

Upgrade to a fixed version: Linux kernel 4.10, 4.15, 4.20, 5.11. Check the vendor advisory for mitigations.

References

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