Bug 2516980 (CVE-2026-74487) - CVE-2026-74487 kernel: binfmt_misc: restore write access when removing an entry
Summary: CVE-2026-74487 kernel: binfmt_misc: restore write access when removing an entry
Keywords:
Status: NEW
Alias: CVE-2026-74487
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
low
low
Target Milestone: ---
Assignee: Product Security DevOps Team
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-08-15 12:42 UTC by OSIDB Bzimport
Modified: 2026-08-21 08:37 UTC (History)
2 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed:
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Description OSIDB Bzimport 2026-08-15 12:42:24 UTC
In the Linux kernel, the following vulnerability has been resolved:

binfmt_misc: restore write access when removing an entry

Registering an entry with the MISC_FMT_OPEN_FILE flag opens the
interpreter via open_exec() which denies write access to it for as
long as the entry exists. Removing the entry closes the interpreter
file via filp_close() but never restores write access, leaving the
inode's i_writecount permanently negative. Opening the interpreter
for writing keeps failing with ETXTBSY long after the entry is gone
until the inode is evicted from the inode cache.

Commit 90f601b497d7 ("binfmt_misc: restore write access before
closing files opened by open_exec()") fixed the same imbalance in the
error path of bm_register_write() but the actual removal path has
been leaking the write denial since the introduction of the flag.

Restore write access in put_binfmt_handler() before closing the
interpreter file.


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