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binfmt_misc: use exe_file_deny_write_access() for the interpreter clone

Type: advisorySources: OSV

In the Linux kernel, the following vulnerability has been resolved: binfmt_misc: use exe_file_deny_write_access() for the interpreter clone For MISC_FMT_OPEN_FILE entries load_misc_binary() clones the registered interpreter file and denies write access to the clone via plain deny_write_access(). The clone is installed as bprm->interpreter and later released by the exec machinery through exe_file_allow_write_access() which skips the i_writecount increment for files with FMODE_FSNOTIFY_HSM set. The deny and allow side can therefore come to different conclusions when pre-content watches are in play: if a pre-content watch is added to the interpreter after registration every subsequent exec through that entry takes a write denial on the clone that is never paired with a write allowance, driving the interpreter inode's i_writecount further down with each exec and leaving the interpreter unwritable even after the entry and all its users are gone. Take the write denial via exe_file_deny_write_access() so both sides of the pairing base their decision on the same file mode, and propagate failure instead of silently ignoring it: an interpreter that is concurrently open for writing now fails the exec with ETXTBSY, exactly like an interpreter freshly opened via open_exec() would.

Products
Kernel
Affected versions
Not specified
Fixed versions
6.18.44, 7.1.8
CVEs
CVE-2026-74486
Confirmed fixed CVEs
Not specified
Updated in this feed
2 Nov 2026, 23:00 UTC · Revision 1

Source evidence

binfmt_misc: use exe_file_deny_write_access() for the interpreter clone

core-osv · Original source

Published 15 Aug 2026, 12:27 UTC

In the Linux kernel, the following vulnerability has been resolved: binfmt_misc: use exe_file_deny_write_access() for the interpreter clone For MISC_FMT_OPEN_FILE entries load_misc_binary() clones the registered interpreter file and denies write access to the clone via plain deny_write_access(). The clone is installed as bprm->interpreter and later released by the exec machinery through exe_file_allow_write_access() which skips the i_writecount increment for files with FMODE_FSNOTIFY_HSM set. The deny and allow side can therefore come to different conclusions when pre-content watches are in play: if a pre-content watch is added to the interpreter after registration every subsequent exec through that entry takes a write denial on the clone that is never paired with a write allowance, driving the interpreter inode's i_writecount further down with each exec and leaving the interpreter unwritable even after the entry and all its users are gone. Take the write denial via exe_file_deny_write_access() so both sides of the pairing base their decision on the same file mode, and propagate failure instead of silently ignoring it: an interpreter that is concurrently open for writing now fails the exec with ETXTBSY, exactly like an interpreter freshly opened via open_exec() would.

osv:CVE-2026-74486

Kernel

Fixed versions: 6.18.44, 7.1.8

Complete source record
{
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  "url": "https://osv.dev/vulnerability/CVE-2026-74486",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "binfmt_misc: use exe_file_deny_write_access() for the interpreter clone",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: binfmt_misc: use exe_file_deny_write_access() for the interpreter clone For MISC_FMT_OPEN_FILE entries load_misc_binary() clones the registered interpreter file and denies write access to the clone via plain deny_write_access(). The clone is installed as bprm->interpreter and later released by the exec machinery through exe_file_allow_write_access() which skips the i_writecount increment for files with FMODE_FSNOTIFY_HSM set. The deny and allow side can therefore come to different conclusions when pre-content watches are in play: if a pre-content watch is added to the interpreter after registration every subsequent exec through that entry takes a write denial on the clone that is never paired with a write allowance, driving the interpreter inode's i_writecount further down with each exec and leaving the interpreter unwritable even after the entry and all its users are gone. Take the write denial via exe_file_deny_write_access() so both sides of the pairing base their decision on the same file mode, and propagate failure instead of silently ignoring it: an interpreter that is concurrently open for writing now fails the exec with ETXTBSY, exactly like an interpreter freshly opened via open_exec() would.",
    "evidence": "osv:CVE-2026-74486",
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      "modified": "2026-10-28T02:30:24.138610179Z",
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  "source_id": "core-osv",
  "document_id": 490700,
  "published_at": "2026-08-15T12:27:17.609+00:00"
}