CVE-2026-23199: In the Linux kernel, the following vulnerability has been resolved: procfs: avoid fetching build ID while holding VMA lock Fix PROCMAP_QUERY to fetch optional…

PriorityP419medium5.5CVSS 3.1

AVLACLPRLUINSUCNINAH

EPSS

0.09%

0.5th percentile

In the Linux kernel, the following vulnerability has been resolved: procfs: avoid fetching build ID while holding VMA lock Fix PROCMAP_QUERY to fetch optional build ID only after dropping mmap_lock or per-VMA lock, whichever was used to lock VMA under question, to avoid deadlock reported by syzbot: -> #1 (&mm->mmap_lock){++++}-{4:4}: __might_fault+0xed/0x170 _copy_to_iter+0x118/0x1720 copy_page_to_iter+0x12d/0x1e0 filemap_read+0x720/0x10a0 blkdev_read_iter+0x2b5/0x4e0 vfs_read+0x7f4/0xae0 ksys_read+0x12a/0x250 do_syscall_64+0xcb/0xf80 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #0 (&sb->s_type->i_mutex_key#8){++++}-{4:4}: __lock_acquire+0x1509/0x26d0 lock_acquire+0x185/0x340 down_read+0x98/0x490 blkdev_read_iter+0x2a7/0x4e0 __kernel_read+0x39a/0xa90 freader_fetch+0x1d5/0xa80 __build_id_parse.isra.0+0xea/0x6a0 do_procmap_query+0xd75/0x1050 procfs_procmap_ioctl+0x7a/0xb0 __x64_sys_ioctl+0x18e/0x210 do_syscall_64+0xcb/0xf80 entry_SYSCALL_64_after_hwframe+0x77/0x7f other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- rlock(&mm->mmap_lock); lock(&sb->s_type->i_mutex_key#8); lock(&mm->mmap_lock); rlock(&sb->s_type->i_mutex_key#8); *** DEADLOCK *** This seems to be exacerbated (as we haven't seen these syzbot reports before that) by the recent: 777a8560fd29 ("lib/buildid: use __kernel_read() for sleepable context") To make this safe, we need to grab file refcount while VMA is still locked, but other than that everything is pretty straightforward. Internal build_id_parse() API assumes VMA is passed, but it only needs the underlying file reference, so just add another variant build_id_parse_file() that expects file passed directly. [[email protected]: fix up kerneldoc]

Affected

10 ranges

Vendor	Product	Version range	Fixed in
debian	linux	< linux 6.18.10-1 (forky)	linux 6.18.10-1 (forky)
linux	linux	—	—
linux	linux	>= ed5d583a88a9207b866c14ba834984c6f3c51d23 < b9b97e6aeb534315f9646b2090d1a5024c6a4e82	b9b97e6aeb534315f9646b2090d1a5024c6a4e82
linux	linux	>= ed5d583a88a9207b866c14ba834984c6f3c51d23 < cbc03ce3e6ce7e21214c3f02218213574c1a2d08	cbc03ce3e6ce7e21214c3f02218213574c1a2d08
linux	linux	>= ed5d583a88a9207b866c14ba834984c6f3c51d23 < b5cbacd7f86f4f62b8813688c8e73be94e8e1951	b5cbacd7f86f4f62b8813688c8e73be94e8e1951
linux	linux_kernel	—	—
linux	linux_kernel	>= 0 < 6.12.73-1	6.12.73-1
linux	linux_kernel	>= 0 < 6.18.10-1	6.18.10-1
linux	linux_kernel	>= 6.11 < 6.12.70	6.12.70
linux	linux_kernel	>= 6.13 < 6.18.10	6.18.10

CVSS provenance

nvdv3.15.5MEDIUMCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

osv5.5MEDIUM

vendor_debian5.5LOW

vendor_redhat5.5MEDIUM

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