CVE-2025-37953

Source
https://nvd.nist.gov/vuln/detail/CVE-2025-37953
Import Source
https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-37953.json
JSON Data
https://api.osv.dev/v1/vulns/CVE-2025-37953
Downstream
Related
Published
2025-05-20T16:01:47Z
Modified
2025-10-22T12:47:37.128642Z
Summary
sch_htb: make htb_deactivate() idempotent
Details

In the Linux kernel, the following vulnerability has been resolved:

schhtb: make htbdeactivate() idempotent

Alan reported a NULL pointer dereference in htbnextrbnode() after we made htbqlen_notify() idempotent.

It turns out in the following case it introduced some regression:

htbdequeuetree(): |-> fqcodeldequeue() |-> qdisctreereducebacklog() |-> htbqlennotify() |-> htbdeactivate() |-> htbnextrbnode() |-> htbdeactivate()

For htbnextrbnode(), after calling the 1st htbdeactivate(), the clprio[prio]->ptr could be already set to NULL, which means htbnextrb_node() is vulnerable here.

For htbdeactivate(), although we checked qlen before calling it, in case of qlen==0 after qdisctreereducebacklog(), we may call it again which triggers the warning inside.

To fix the issues here, we need to:

1) Make htbdeactivate() idempotent, that is, simply return if we already call it before. 2) Make htbnextrbnode() safe against ptr==NULL.

Many thanks to Alan for testing and for the reproducer.

References

Affected packages

Git / git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git

Affected ranges

Type
GIT
Repo
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Events
Introduced
e6b45f4de763b00dc1c55e685e2dd1aaf525d3c1
Fixed
99ff8a20fd61315bf9ae627440a5ff07d22ee153
Type
GIT
Repo
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Events
Introduced
32ae12ce6a9f6bace186ca7335220ff59b6cc3cd
Fixed
a9945f7cf1709adc5d2d31cb6cfc85627ce299a8
Type
GIT
Repo
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Events
Introduced
967955c9e57f8eebfccc298037d4aaf3d42bc1c9
Fixed
c2d25fddd867ce20a266806634eeeb5c30cb520c
Type
GIT
Repo
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Events
Introduced
73cf6af13153d62f9b76eff422eea79dbc70f15e
Fixed
c928dd4f6bf0c25c72b11824a1e9ac9bd37296a0
Type
GIT
Repo
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Events
Introduced
bbbf5e0f87078b715e7a665d662a2c0e77f044ae
Fixed
31ff70ad39485698cf779f2078132d80b57f6c07
Type
GIT
Repo
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Events
Introduced
0a188c0e197383683fd093ab1ea6ce9a5869a6ea
Fixed
98cd7ed92753090a714f0802d4434314526fe61d
Type
GIT
Repo
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Events
Introduced
a61f1b5921761fbaf166231418bc1db301e5bf59
Fixed
c4792b9e38d2f61b07eac72f10909fa76130314b
Type
GIT
Repo
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Events
Introduced
5ba8b837b522d7051ef81bacf3d95383ff8edce5
Fixed
3769478610135e82b262640252d90f6efb05be71

Affected versions

v6.*

v6.1.138
v6.12.28
v6.14.6
v6.15-rc1
v6.15-rc2
v6.15-rc3
v6.15-rc4
v6.6.90

Linux / Kernel

Package

Name
Kernel

Affected ranges

Type
ECOSYSTEM
Events
Introduced
6.1.138
Fixed
6.1.139
Type
ECOSYSTEM
Events
Introduced
6.6.90
Fixed
6.6.91
Type
ECOSYSTEM
Events
Introduced
6.12.28
Fixed
6.12.29
Type
ECOSYSTEM
Events
Introduced
6.14.6
Fixed
6.14.7