CVE-2025-37953
published 2025-05-20CVE-2025-37953: In the Linux kernel, the following vulnerability has been resolved: sch_htb: make htb_deactivate() idempotent Alan reported a NULL pointer dereference in…
medium5.5CVSS 3.1
AVLACLPRLUINSUCNINAH
In the Linux kernel, the following vulnerability has been resolved:
sch_htb: make htb_deactivate() idempotent
Alan reported a NULL pointer dereference in htb_next_rb_node()
after we made htb_qlen_notify() idempotent.
It turns out in the following case it introduced some regression:
htb_dequeue_tree():
|-> fq_codel_dequeue()
|-> qdisc_tree_reduce_backlog()
|-> htb_qlen_notify()
|-> htb_deactivate()
|-> htb_next_rb_node()
|-> htb_deactivate()
For htb_next_rb_node(), after calling the 1st htb_deactivate(), the
clprio[prio]->ptr could be already set to NULL, which means
htb_next_rb_node() is vulnerable here.
For htb_deactivate(), although we checked qlen before calling it, in
case of qlen==0 after qdisc_tree_reduce_backlog(), we may call it again
which triggers the warning inside.
To fix the issues here, we need to:
1) Make htb_deactivate() idempotent, that is, simply return if we
already call it before.
2) Make htb_next_rb_node() safe against ptr==NULL.
Many thanks to Alan for testing and for the reproducer.
Affected
23 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| debian | debian_linux | — | — |
| debian | linux | < linux 6.1.140-1 (bookworm) | linux 6.1.140-1 (bookworm) |
| debian | linux-6.1 | < linux 6.1.140-1 (bookworm) | linux 6.1.140-1 (bookworm) |
| linux | linux | >= 0a188c0e197383683fd093ab1ea6ce9a5869a6ea < 98cd7ed92753090a714f0802d4434314526fe61d | 98cd7ed92753090a714f0802d4434314526fe61d |
| linux | linux | >= 32ae12ce6a9f6bace186ca7335220ff59b6cc3cd < a9945f7cf1709adc5d2d31cb6cfc85627ce299a8 | a9945f7cf1709adc5d2d31cb6cfc85627ce299a8 |
| linux | linux | >= 5ba8b837b522d7051ef81bacf3d95383ff8edce5 < 3769478610135e82b262640252d90f6efb05be71 | 3769478610135e82b262640252d90f6efb05be71 |
| linux | linux | >= 6.1.138 < 6.1.139 | 6.1.139 |
| linux | linux | >= 6.12.28 < 6.12.29 | 6.12.29 |
| linux | linux | >= 6.14.6 < 6.14.7 | 6.14.7 |
| linux | linux | >= 6.6.90 < 6.6.91 | 6.6.91 |
| linux | linux | >= 73cf6af13153d62f9b76eff422eea79dbc70f15e < c928dd4f6bf0c25c72b11824a1e9ac9bd37296a0 | c928dd4f6bf0c25c72b11824a1e9ac9bd37296a0 |
| linux | linux | >= 967955c9e57f8eebfccc298037d4aaf3d42bc1c9 < c2d25fddd867ce20a266806634eeeb5c30cb520c | c2d25fddd867ce20a266806634eeeb5c30cb520c |
| linux | linux | >= a61f1b5921761fbaf166231418bc1db301e5bf59 < c4792b9e38d2f61b07eac72f10909fa76130314b | c4792b9e38d2f61b07eac72f10909fa76130314b |
| linux | linux | >= bbbf5e0f87078b715e7a665d662a2c0e77f044ae < 31ff70ad39485698cf779f2078132d80b57f6c07 | 31ff70ad39485698cf779f2078132d80b57f6c07 |
| linux | linux | >= e6b45f4de763b00dc1c55e685e2dd1aaf525d3c1 < 99ff8a20fd61315bf9ae627440a5ff07d22ee153 | 99ff8a20fd61315bf9ae627440a5ff07d22ee153 |
| linux | linux_kernel | — | — |
| linux | linux_kernel | — | — |
| linux | linux_kernel | — | — |
| linux | linux_kernel | — | — |
| linux | linux_kernel | — | — |
| linux | linux_kernel | >= 0 < 6.1.140-1 | 6.1.140-1 |
| linux | linux_kernel | >= 0 < 6.12.29-1 | 6.12.29-1 |
| linux | linux_kernel | >= 0 < 6.12.29-1 | 6.12.29-1 |
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
Red Hat
kernel: Linux kernel: sch_htb NULL pointer dereference
vendor_redhat·2025-05-20·CVSS 5.5
CVE-2025-37953 [MEDIUM] CWE-476 kernel: Linux kernel: sch_htb NULL pointer dereference
kernel: Linux kernel: sch_htb NULL pointer dereference
In the Linux kernel, the following vulnerability has been resolved:
sch_htb: make htb_deactivate() idempotent
Alan reported a NULL pointer dereference in htb_next_rb_node()
after we made htb_qlen_notify() idempotent.
It turns out in the following case it introduced some regression:
htb_dequeue_tree():
|-> fq_codel_dequeue()
|-> qdisc_tree_reduce_backlog()
|-> htb_qlen_notify()
|-> htb_deactivate()
|-> htb_next_rb_node()
|-> htb_deactivate()
For htb_next_rb_node(), after calling the 1st htb_deactivate(), the
clprio[prio]->ptr could be already set to NULL, which means
htb_next_rb_node() is vulnerable here.
For htb_deactivate(), although we checked qlen before calling it, in
case of qlen==0 after qdisc_tree_reduce_backlog(), we may call
Debian
CVE-2025-37953: linux - In the Linux kernel, the following vulnerability has been resolved: sch_htb: ma...
vendor_debian·2025·CVSS 5.5
CVE-2025-37953 [MEDIUM] CVE-2025-37953: linux - In the Linux kernel, the following vulnerability has been resolved: sch_htb: ma...
In the Linux kernel, the following vulnerability has been resolved: sch_htb: make htb_deactivate() idempotent Alan reported a NULL pointer dereference in htb_next_rb_node() after we made htb_qlen_notify() idempotent. It turns out in the following case it introduced some regression: htb_dequeue_tree(): |-> fq_codel_dequeue() |-> qdisc_tree_reduce_backlog() |-> htb_qlen_notify() |-> htb_deactivate() |-> htb_next_rb_node() |-> htb_deactivate() For htb_next_rb_node(), after calling the 1st htb_deactivate(), the clprio[prio]->ptr could be already set to NULL, which means htb_next_rb_node() is vulnerable here. For htb_deactivate(), although we checked qlen before calling it, in case of qlen==0 after qdisc_tree_reduce_backlog(), we may call it again which triggers the warning inside. To fix the i
OSV
CVE-2025-37953: In the Linux kernel, the following vulnerability has been resolved: sch_htb: make htb_deactivate() idempotent Alan reported a NULL pointer dereference
osv·2025-05-20·CVSS 5.5
CVE-2025-37953 [MEDIUM] CVE-2025-37953: In the Linux kernel, the following vulnerability has been resolved: sch_htb: make htb_deactivate() idempotent Alan reported a NULL pointer dereference
In the Linux kernel, the following vulnerability has been resolved: sch_htb: make htb_deactivate() idempotent Alan reported a NULL pointer dereference in htb_next_rb_node() after we made htb_qlen_notify() idempotent. It turns out in the following case it introduced some regression: htb_dequeue_tree(): |-> fq_codel_dequeue() |-> qdisc_tree_reduce_backlog() |-> htb_qlen_notify() |-> htb_deactivate() |-> htb_next_rb_node() |-> htb_deactivate() For htb_next_rb_node(), after calling the 1st htb_deactivate(), the clprio[prio]->ptr could be already set to NULL, which means htb_next_rb_node() is vulnerable here. For htb_deactivate(), although we checked qlen before calling it, in case of qlen==0 after qdisc_tree_reduce_backlog(), we may call it again which triggers the warning inside. To fix the i
GHSA
GHSA-ccmh-pfgg-525g: In the Linux kernel, the following vulnerability has been resolved:
sch_htb: make htb_deactivate() idempotent
Alan reported a NULL pointer dereferen
ghsa_unreviewed·2025-05-20
CVE-2025-37953 [MEDIUM] CWE-476 GHSA-ccmh-pfgg-525g: In the Linux kernel, the following vulnerability has been resolved:
sch_htb: make htb_deactivate() idempotent
Alan reported a NULL pointer dereferen
In the Linux kernel, the following vulnerability has been resolved:
sch_htb: make htb_deactivate() idempotent
Alan reported a NULL pointer dereference in htb_next_rb_node()
after we made htb_qlen_notify() idempotent.
It turns out in the following case it introduced some regression:
htb_dequeue_tree():
|-> fq_codel_dequeue()
|-> qdisc_tree_reduce_backlog()
|-> htb_qlen_notify()
|-> htb_deactivate()
|-> htb_next_rb_node()
|-> htb_deactivate()
For htb_next_rb_node(), after calling the 1st htb_deactivate(), the
clprio[prio]->ptr could be already set to NULL, which means
htb_next_rb_node() is vulnerable here.
For htb_deactivate(), although we checked qlen before calling it, in
case of qlen==0 after qdisc_tree_reduce_backlog(), we may call it again
which triggers the warning inside.
To fi
No detection rules found.
No public exploits indexed.
No writeups or analysis indexed.
https://git.kernel.org/stable/c/31ff70ad39485698cf779f2078132d80b57f6c07https://git.kernel.org/stable/c/3769478610135e82b262640252d90f6efb05be71https://git.kernel.org/stable/c/98cd7ed92753090a714f0802d4434314526fe61dhttps://git.kernel.org/stable/c/99ff8a20fd61315bf9ae627440a5ff07d22ee153https://git.kernel.org/stable/c/a9945f7cf1709adc5d2d31cb6cfc85627ce299a8https://git.kernel.org/stable/c/c2d25fddd867ce20a266806634eeeb5c30cb520chttps://git.kernel.org/stable/c/c4792b9e38d2f61b07eac72f10909fa76130314bhttps://git.kernel.org/stable/c/c928dd4f6bf0c25c72b11824a1e9ac9bd37296a0https://lists.debian.org/debian-lts-announce/2025/08/msg00010.html
2025-05-20
Published