net_sched: drr: Fix double list add in class with netem as child qdisc
As described in Gerrard's report [1], there are use cases where a netem
child qdisc will make the parent qdisc's enqueue callback reentrant.
In the case of drr, there won't be a UAF, but the code will add the same
classifier to the list twice, which will cause memory corruption.
In addition to checking for qlen being zero, this patch checks whether the
class was already added to the active_list (cl_is_active) before adding
to the list to cover for the reentrant case.
[1] https://lore.kernel.org/netdev/CAHcdcOm+03OD2j6R0=YHKqmy=VgJ8xEOKuP6c7mSgnp-TEJJbw@mail.gmail.com/
Metrics
Affected Vendors & Products
| Source | ID | Title |
|---|---|---|
Debian DLA |
DLA-4271-1 | linux-6.1 security update |
Debian DLA |
DLA-4327-1 | linux security update |
Debian DSA |
DSA-5925-1 | linux security update |
EUVD |
EUVD-2025-15931 | In the Linux kernel, the following vulnerability has been resolved: net_sched: drr: Fix double list add in class with netem as child qdisc As described in Gerrard's report [1], there are use cases where a netem child qdisc will make the parent qdisc's enqueue callback reentrant. In the case of drr, there won't be a UAF, but the code will add the same classifier to the list twice, which will cause memory corruption. In addition to checking for qlen being zero, this patch checks whether the class was already added to the active_list (cl_is_active) before adding to the list to cover for the reentrant case. [1] https://lore.kernel.org/netdev/CAHcdcOm+03OD2j6R0=YHKqmy=VgJ8xEOKuP6c7mSgnp-TEJJbw@mail.gmail.com/ |
Ubuntu USN |
USN-7649-1 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-7649-2 | Linux kernel (AWS) vulnerabilities |
Ubuntu USN |
USN-7650-1 | Linux kernel (OEM) vulnerabilities |
Ubuntu USN |
USN-7654-1 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-7654-2 | Linux kernel (Real-time) vulnerabilities |
Ubuntu USN |
USN-7654-3 | Linux kernel (FIPS) vulnerabilities |
Ubuntu USN |
USN-7654-4 | Linux kernel (KVM) vulnerabilities |
Ubuntu USN |
USN-7654-5 | Linux kernel (Xilinx ZynqMP) vulnerabilities |
Ubuntu USN |
USN-7655-1 | Linux kernel (Intel IoTG) vulnerabilities |
Ubuntu USN |
USN-7665-1 | Linux kernel (Oracle) vulnerabilities |
Ubuntu USN |
USN-7665-2 | Linux kernel (AWS) vulnerabilities |
Ubuntu USN |
USN-7686-1 | Linux kernel (Raspberry Pi) vulnerabilities |
Ubuntu USN |
USN-7711-1 | Linux kernel (Azure) vulnerabilities |
Ubuntu USN |
USN-7712-1 | Linux kernel (Azure FIPS) vulnerabilities |
Ubuntu USN |
USN-7712-2 | Linux kernel (Azure) vulnerabilities |
Ubuntu USN |
USN-7721-1 | Linux kernel (Azure) vulnerabilities |
Solution
No solution given by the vendor.
Workaround
No workaround given by the vendor.
Mon, 03 Nov 2025 20:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| References |
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Mon, 03 Nov 2025 18:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| References |
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Mon, 14 Jul 2025 13:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Metrics |
epss
|
epss
|
Wed, 04 Jun 2025 13:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| References |
|
Fri, 23 May 2025 06:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Weaknesses | CWE-367 | |
| Metrics |
cvssV3_1
|
cvssV3_1
|
Wed, 21 May 2025 03:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| References |
| |
| Metrics |
threat_severity
|
cvssV3_1
|
Tue, 20 May 2025 15:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | In the Linux kernel, the following vulnerability has been resolved: net_sched: drr: Fix double list add in class with netem as child qdisc As described in Gerrard's report [1], there are use cases where a netem child qdisc will make the parent qdisc's enqueue callback reentrant. In the case of drr, there won't be a UAF, but the code will add the same classifier to the list twice, which will cause memory corruption. In addition to checking for qlen being zero, this patch checks whether the class was already added to the active_list (cl_is_active) before adding to the list to cover for the reentrant case. [1] https://lore.kernel.org/netdev/CAHcdcOm+03OD2j6R0=YHKqmy=VgJ8xEOKuP6c7mSgnp-TEJJbw@mail.gmail.com/ | |
| Title | net_sched: drr: Fix double list add in class with netem as child qdisc | |
| References |
|
|
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2025-11-03T19:57:17.858Z
Reserved: 2025-04-16T04:51:23.967Z
Link: CVE-2025-37915
No data.
Status : Awaiting Analysis
Published: 2025-05-20T16:15:28.057
Modified: 2025-11-03T20:18:41.430
Link: CVE-2025-37915
OpenCVE Enrichment
Updated: 2025-06-27T09:26:51Z
Debian DLA
Debian DSA
EUVD
Ubuntu USN