CVE-2021-47125
Linux Kernel sch_htb NULL Pointer Dereference Reference Count Leak
Description
In the Linux kernel, the following vulnerability has been resolved: sch_htb: fix refcount leak in htb_parent_to_leaf_offload The commit ae81feb7338c ("sch_htb: fix null pointer dereference on a null new_q") fixes a NULL pointer dereference bug, but it is not correct. Because htb_graft_helper properly handles the case when new_q is NULL, and after the previous patch by skipping this call which creates an inconsistency : dev_queue->qdisc will still point to the old qdisc, but cl->parent->leaf.q will point to the new one (which will be noop_qdisc, because new_q was NULL). The code is based on an assumption that these two pointers are the same, so it can lead to refcount leaks. The correct fix is to add a NULL pointer check to protect qdisc_refcount_inc inside htb_parent_to_leaf_offload.
INFO
Published Date :
March 15, 2024, 9:15 p.m.
Last Modified :
Jan. 7, 2025, 6 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
- There is no known solution at this time.
Public PoC/Exploit Available at Github
CVE-2021-47125 has a 1 public
PoC/Exploit available at Github.
Go to the Public Exploits tab to see the list.
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-2021-47125.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2021-47125 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-2021-47125
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).
Ini adalah repository kumpulan CVE v.5
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Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2021-47125 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2021-47125 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]
Jan. 07, 2025
Action Type Old Value New Value Added CVSS V3.1 NIST AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H Added CWE NIST NVD-CWE-Other Added CPE Configuration OR *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 5.12 up to (excluding) 5.12.10 *cpe:2.3:o:linux:linux_kernel:5.13:rc1:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:5.13:rc2:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:5.13:rc3:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:5.13:rc4:*:*:*:*:*:* Changed Reference Type https://git.kernel.org/stable/c/2411c02d03892a5057499f8102d0cc1e0f852416 No Types Assigned https://git.kernel.org/stable/c/2411c02d03892a5057499f8102d0cc1e0f852416 Patch Changed Reference Type https://git.kernel.org/stable/c/2411c02d03892a5057499f8102d0cc1e0f852416 No Types Assigned https://git.kernel.org/stable/c/2411c02d03892a5057499f8102d0cc1e0f852416 Patch Changed Reference Type https://git.kernel.org/stable/c/944d671d5faa0d78980a3da5c0f04960ef1ad893 No Types Assigned https://git.kernel.org/stable/c/944d671d5faa0d78980a3da5c0f04960ef1ad893 Patch Changed Reference Type https://git.kernel.org/stable/c/944d671d5faa0d78980a3da5c0f04960ef1ad893 No Types Assigned https://git.kernel.org/stable/c/944d671d5faa0d78980a3da5c0f04960ef1ad893 Patch -
CVE Modified by af854a3a-2127-422b-91ae-364da2661108
Nov. 21, 2024
Action Type Old Value New Value Added Reference https://git.kernel.org/stable/c/2411c02d03892a5057499f8102d0cc1e0f852416 Added Reference https://git.kernel.org/stable/c/944d671d5faa0d78980a3da5c0f04960ef1ad893 -
CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
May. 28, 2024
Action Type Old Value New Value -
CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
May. 14, 2024
Action Type Old Value New Value -
CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Mar. 15, 2024
Action Type Old Value New Value Added Description In the Linux kernel, the following vulnerability has been resolved: sch_htb: fix refcount leak in htb_parent_to_leaf_offload The commit ae81feb7338c ("sch_htb: fix null pointer dereference on a null new_q") fixes a NULL pointer dereference bug, but it is not correct. Because htb_graft_helper properly handles the case when new_q is NULL, and after the previous patch by skipping this call which creates an inconsistency : dev_queue->qdisc will still point to the old qdisc, but cl->parent->leaf.q will point to the new one (which will be noop_qdisc, because new_q was NULL). The code is based on an assumption that these two pointers are the same, so it can lead to refcount leaks. The correct fix is to add a NULL pointer check to protect qdisc_refcount_inc inside htb_parent_to_leaf_offload. Added Reference kernel.org https://git.kernel.org/stable/c/2411c02d03892a5057499f8102d0cc1e0f852416 [No types assigned] Added Reference kernel.org https://git.kernel.org/stable/c/944d671d5faa0d78980a3da5c0f04960ef1ad893 [No types assigned]