CVE-2026-52997
net/sched: sch_dualpi2: drain both C-queue and L-queue in dualpi2_change()
Description
In the Linux kernel, the following vulnerability has been resolved: net/sched: sch_dualpi2: drain both C-queue and L-queue in dualpi2_change() Fix dualpi2_change() to correctly enforce updated limit and memlimit values after a configuration change of the dualpi2 qdisc. Before this patch, dualpi2_change() always attempted to dequeue packets via the root qdisc (C-queue) when reducing backlog or memory usage, and unconditionally assumed that a valid skb will be returned. When traffic classification results in packets being queued in the L-queue while the C-queue is empty, this leads to a NULL skb dereference during limit or memlimit enforcement. This is fixed by first dequeuing from the C-queue path if it is non-empty. Once the C-queue is empty, packets are dequeued directly from the L-queue. Return values from qdisc_dequeue_internal() are checked for both queues. When dequeuing from the L-queue, the parent qdisc qlen and backlog counters are updated explicitly to keep overall qdisc statistics consistent.
INFO
Published Date :
June 24, 2026, 5:17 p.m.
Last Modified :
July 15, 2026, 12:56 p.m.
Remotely Exploit :
No
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | MEDIUM | [email protected] |
Solution
- Update the Linux kernel to include the fix.
- Ensure proper packet dequeuing from C-queue and L-queue.
- Verify qdisc statistics update after changes.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-52997.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-52997 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-52997
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-52997 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-52997 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Initial Analysis by [email protected]
Jul. 15, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H Added CWE CWE-476 Added CPE Configuration OR *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.19 up to (excluding) 7.0.10 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.17 up to (excluding) 6.18.33 Added Reference Type kernel.org: https://git.kernel.org/stable/c/3042add80c2c50bd127d570b83319af612efde65 Types: Patch Added Reference Type kernel.org: https://git.kernel.org/stable/c/478ed6b7d2577439c610f91fa8759a4c878a4264 Types: Patch Added Reference Type kernel.org: https://git.kernel.org/stable/c/86cf2eba2056bcf9c41fba260e599bd95bf9943b Types: Patch -
New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Jun. 24, 2026
Action Type Old Value New Value Added Affected [{'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '320d031ad6e4d67e8e1ab08ac71efda02bc85683', 'lessThan': '86cf2eba2056bcf9c41fba260e599bd95bf9943b', 'versionType': 'git'}, {'status': 'affected', 'version': '320d031ad6e4d67e8e1ab08ac71efda02bc85683', 'lessThan': '3042add80c2c50bd127d570b83319af612efde65', 'versionType': 'git'}, {'status': 'affected', 'version': '320d031ad6e4d67e8e1ab08ac71efda02bc85683', 'lessThan': '478ed6b7d2577439c610f91fa8759a4c878a4264', 'versionType': 'git'}], 'programFiles': ['net/sched/sch_dualpi2.c'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '6.17'}, {'status': 'unaffected', 'version': '0', 'lessThan': '6.17', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '6.18.33', 'versionType': 'semver', 'lessThanOrEqual': '6.18.*'}, {'status': 'unaffected', 'version': '7.0.10', 'versionType': 'semver', 'lessThanOrEqual': '7.0.*'}, {'status': 'unaffected', 'version': '7.1', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['net/sched/sch_dualpi2.c'], 'defaultStatus': 'affected'}] Added Description In the Linux kernel, the following vulnerability has been resolved: net/sched: sch_dualpi2: drain both C-queue and L-queue in dualpi2_change() Fix dualpi2_change() to correctly enforce updated limit and memlimit values after a configuration change of the dualpi2 qdisc. Before this patch, dualpi2_change() always attempted to dequeue packets via the root qdisc (C-queue) when reducing backlog or memory usage, and unconditionally assumed that a valid skb will be returned. When traffic classification results in packets being queued in the L-queue while the C-queue is empty, this leads to a NULL skb dereference during limit or memlimit enforcement. This is fixed by first dequeuing from the C-queue path if it is non-empty. Once the C-queue is empty, packets are dequeued directly from the L-queue. Return values from qdisc_dequeue_internal() are checked for both queues. When dequeuing from the L-queue, the parent qdisc qlen and backlog counters are updated explicitly to keep overall qdisc statistics consistent. Added Reference https://git.kernel.org/stable/c/3042add80c2c50bd127d570b83319af612efde65 Added Reference https://git.kernel.org/stable/c/478ed6b7d2577439c610f91fa8759a4c878a4264 Added Reference https://git.kernel.org/stable/c/86cf2eba2056bcf9c41fba260e599bd95bf9943b