CVE-2023-53728
published 2025-10-22CVE-2023-53728: In the Linux kernel, the following vulnerability has been resolved: posix-timers: Ensure timer ID search-loop limit is valid posix_timer_add() tries to…
PriorityP421low5.5
EPSS
0.19%
9.4th percentile
In the Linux kernel, the following vulnerability has been resolved:
posix-timers: Ensure timer ID search-loop limit is valid
posix_timer_add() tries to allocate a posix timer ID by starting from the
cached ID which was stored by the last successful allocation.
This is done in a loop searching the ID space for a free slot one by
one. The loop has to terminate when the search wrapped around to the
starting point.
But that's racy vs. establishing the starting point. That is read out
lockless, which leads to the following problem:
CPU0 CPU1
posix_timer_add()
start = sig->posix_timer_id;
lock(hash_lock);
... posix_timer_add()
if (++sig->posix_timer_id posix_timer_id;
sig->posix_timer_id = 0;
So CPU1 can observe a negative start value, i.e. -1, and the loop break
never happens because the condition can never be true:
if (sig->posix_timer_id == start)
break;
While this is unlikely to ever turn into an endless loop as the ID space is
huge (INT_MAX), the racy read of the start value caught the attention of
KCSAN and Dmitry unearthed that incorrectness.
Rewrite it so that all id operations are under the hash lock.
Affected
21 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| debian | linux | < linux 6.1.112-1 (bookworm) | linux 6.1.112-1 (bookworm) |
| linux | linux | — | — |
| linux | linux | >= 5ed67f05f66c41e39880a6d61358438a25f9fee5 < 8dc52c200b889bc1cb34288fbf623d4ff381d2ae | 8dc52c200b889bc1cb34288fbf623d4ff381d2ae |
| linux | linux | >= 5ed67f05f66c41e39880a6d61358438a25f9fee5 < 9ea26a8494a0a9337e7415eafd6f3ed940327dc5 | 9ea26a8494a0a9337e7415eafd6f3ed940327dc5 |
| linux | linux | >= 5ed67f05f66c41e39880a6d61358438a25f9fee5 < 8ad6679a5bb97cdb3e14942729292b4bfcc0e223 | 8ad6679a5bb97cdb3e14942729292b4bfcc0e223 |
| linux | linux | >= 5ed67f05f66c41e39880a6d61358438a25f9fee5 < 322377cc909defcca9451487484845e7e1d20d1b | 322377cc909defcca9451487484845e7e1d20d1b |
| linux | linux | >= 5ed67f05f66c41e39880a6d61358438a25f9fee5 < ef535e0315afd098c4beb1da364847eca4b56a20 | ef535e0315afd098c4beb1da364847eca4b56a20 |
| linux | linux | >= 5ed67f05f66c41e39880a6d61358438a25f9fee5 < 6a0ac84501b4fec73a1a823c55cf13584c43f418 | 6a0ac84501b4fec73a1a823c55cf13584c43f418 |
| linux | linux | >= 5ed67f05f66c41e39880a6d61358438a25f9fee5 < 37175e25edf7cc0d5a2cd2c2a1cbe2dcbf4a1937 | 37175e25edf7cc0d5a2cd2c2a1cbe2dcbf4a1937 |
| linux | linux | >= 5ed67f05f66c41e39880a6d61358438a25f9fee5 < 8ce8849dd1e78dadcee0ec9acbd259d239b7069f | 8ce8849dd1e78dadcee0ec9acbd259d239b7069f |
| linux | linux_kernel | >= 0 < 5.10.191-1 | 5.10.191-1 |
| linux | linux_kernel | >= 0 < 6.1.112-1 | 6.1.112-1 |
| linux | linux_kernel | >= 0 < 6.4.11-1 | 6.4.11-1 |
| linux | linux_kernel | >= 0 < 6.4.11-1 | 6.4.11-1 |
| linux | linux_kernel | >= 3.10.0 < 4.14.322 | 4.14.322 |
| linux | linux_kernel | >= 4.15.0 < 4.19.291 | 4.19.291 |
| linux | linux_kernel | >= 4.20.0 < 5.4.251 | 5.4.251 |
| linux | linux_kernel | >= 5.11.0 < 5.15.150 | 5.15.150 |
| linux | linux_kernel | >= 5.16.0 < 6.1.107 | 6.1.107 |
| linux | linux_kernel | >= 5.5.0 < 5.10.188 | 5.10.188 |
| linux | linux_kernel | >= 6.2.0 < 6.4.7 | 6.4.7 |
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Red Hat
kernel: posix-timers: Ensure timer ID search-loop limit is valid
vendor_redhat·2025-10-22·CVSS 5.5
CVE-2023-53728 [LOW] CWE-367 kernel: posix-timers: Ensure timer ID search-loop limit is valid
kernel: posix-timers: Ensure timer ID search-loop limit is valid
In the Linux kernel, the following vulnerability has been resolved:
posix-timers: Ensure timer ID search-loop limit is valid
posix_timer_add() tries to allocate a posix timer ID by starting from the
cached ID which was stored by the last successful allocation.
This is done in a loop searching the ID space for a free slot one by
one. The loop has to terminate when the search wrapped around to the
starting point.
But that's racy vs. establishing the starting point. That is read out
lockless, which leads to the following problem:
CPU0 CPU1
posix_timer_add()
start = sig->posix_timer_id;
lock(hash_lock);
... posix_timer_add()
if (++sig->posix_timer_id posix_timer_id;
sig->posix_timer_id = 0;
So CPU1 can observe a negative start v
Debian
CVE-2023-53728: linux - In the Linux kernel, the following vulnerability has been resolved: posix-timer...
vendor_debian·2023
CVE-2023-53728 CVE-2023-53728: linux - In the Linux kernel, the following vulnerability has been resolved: posix-timer...
In the Linux kernel, the following vulnerability has been resolved: posix-timers: Ensure timer ID search-loop limit is valid posix_timer_add() tries to allocate a posix timer ID by starting from the cached ID which was stored by the last successful allocation. This is done in a loop searching the ID space for a free slot one by one. The loop has to terminate when the search wrapped around to the starting point. But that's racy vs. establishing the starting point. That is read out lockless, which leads to the following problem: CPU0 CPU1 posix_timer_add() start = sig->posix_timer_id; lock(hash_lock); ... posix_timer_add() if (++sig->posix_timer_id posix_timer_id; sig->posix_timer_id = 0; So CPU1 can observe a negative start value, i.e. -1, and the loop break never happens because the condit
OSV
CVE-2023-53728: In the Linux kernel, the following vulnerability has been resolved: posix-timers: Ensure timer ID search-loop limit is valid posix_timer_add() tries t
osv·2025-10-22
CVE-2023-53728 CVE-2023-53728: In the Linux kernel, the following vulnerability has been resolved: posix-timers: Ensure timer ID search-loop limit is valid posix_timer_add() tries t
In the Linux kernel, the following vulnerability has been resolved: posix-timers: Ensure timer ID search-loop limit is valid posix_timer_add() tries to allocate a posix timer ID by starting from the cached ID which was stored by the last successful allocation. This is done in a loop searching the ID space for a free slot one by one. The loop has to terminate when the search wrapped around to the starting point. But that's racy vs. establishing the starting point. That is read out lockless, which leads to the following problem: CPU0 CPU1 posix_timer_add() start = sig->posix_timer_id; lock(hash_lock); ... posix_timer_add() if (++sig->posix_timer_id posix_timer_id; sig->posix_timer_id = 0; So CPU1 can observe a negative start value, i.e. -1, and the loop break never happens because the condit
OSV
posix-timers: Ensure timer ID search-loop limit is valid
osv·2025-10-22
CVE-2023-53728 posix-timers: Ensure timer ID search-loop limit is valid
posix-timers: Ensure timer ID search-loop limit is valid
In the Linux kernel, the following vulnerability has been resolved:
posix-timers: Ensure timer ID search-loop limit is valid
posix_timer_add() tries to allocate a posix timer ID by starting from the
cached ID which was stored by the last successful allocation.
This is done in a loop searching the ID space for a free slot one by
one. The loop has to terminate when the search wrapped around to the
starting point.
But that's racy vs. establishing the starting point. That is read out
lockless, which leads to the following problem:
CPU0 CPU1
posix_timer_add()
start = sig->posix_timer_id;
lock(hash_lock);
... posix_timer_add()
if (++sig->posix_timer_id posix_timer_id;
sig->posix_timer_id = 0;
So CPU1 can observe a negative start val
GHSA
GHSA-2cvf-73cf-jrw5: In the Linux kernel, the following vulnerability has been resolved:
posix-timers: Ensure timer ID search-loop limit is valid
posix_timer_add() tries
ghsa_unreviewed·2025-10-22
CVE-2023-53728 GHSA-2cvf-73cf-jrw5: In the Linux kernel, the following vulnerability has been resolved:
posix-timers: Ensure timer ID search-loop limit is valid
posix_timer_add() tries
In the Linux kernel, the following vulnerability has been resolved:
posix-timers: Ensure timer ID search-loop limit is valid
posix_timer_add() tries to allocate a posix timer ID by starting from the
cached ID which was stored by the last successful allocation.
This is done in a loop searching the ID space for a free slot one by
one. The loop has to terminate when the search wrapped around to the
starting point.
But that's racy vs. establishing the starting point. That is read out
lockless, which leads to the following problem:
CPU0 CPU1
posix_timer_add()
start = sig->posix_timer_id;
lock(hash_lock);
... posix_timer_add()
if (++sig->posix_timer_id posix_timer_id;
sig->posix_timer_id = 0;
So CPU1 can observe a negative start value, i.e. -1, and the loop break
never happens because the
No detection rules found.
No public exploits indexed.
https://git.kernel.org/stable/c/322377cc909defcca9451487484845e7e1d20d1bhttps://git.kernel.org/stable/c/37175e25edf7cc0d5a2cd2c2a1cbe2dcbf4a1937https://git.kernel.org/stable/c/6a0ac84501b4fec73a1a823c55cf13584c43f418https://git.kernel.org/stable/c/8ad6679a5bb97cdb3e14942729292b4bfcc0e223https://git.kernel.org/stable/c/8ce8849dd1e78dadcee0ec9acbd259d239b7069fhttps://git.kernel.org/stable/c/8dc52c200b889bc1cb34288fbf623d4ff381d2aehttps://git.kernel.org/stable/c/9ea26a8494a0a9337e7415eafd6f3ed940327dc5https://git.kernel.org/stable/c/ef535e0315afd098c4beb1da364847eca4b56a20
2025-10-22
Published