7.5
HIGH CVSS 3.1
CVE-2021-47295
net: sched: fix memory leak in tcindex_partial_destroy_work
Description

In the Linux kernel, the following vulnerability has been resolved: net: sched: fix memory leak in tcindex_partial_destroy_work Syzbot reported memory leak in tcindex_set_parms(). The problem was in non-freed perfect hash in tcindex_partial_destroy_work(). In tcindex_set_parms() new tcindex_data is allocated and some fields from old one are copied to new one, but not the perfect hash. Since tcindex_partial_destroy_work() is the destroy function for old tcindex_data, we need to free perfect hash to avoid memory leak.

INFO

Published Date :

May 21, 2024, 3:15 p.m.

Last Modified :

Dec. 6, 2025, 5:16 a.m.

Remotely Exploit :

Yes !

Source :

416baaa9-dc9f-4396-8d5f-8c081fb06d67
Affected Products

The following products are affected by CVE-2021-47295 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

ID Vendor Product Action
1 Linux linux_kernel
CVSS Scores
The Common Vulnerability Scoring System is a standardized framework for assessing the severity of vulnerabilities in software and systems. We collect and displays CVSS scores from various sources for each CVE.
Score Version Severity Vector Exploitability Score Impact Score Source
CVSS 3.1 HIGH 134c704f-9b21-4f2e-91b3-4a467353bcc0
Solution
This issue can be resolved by updating the Linux kernel to a patched version.
  • Update the Linux kernel packages.
  • Reboot the system to apply the update.
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2021-47295 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-2021-47295 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-2021-47295 vulnerability anywhere in the article.

The following table lists the changes that have been made to the CVE-2021-47295 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.

  • CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67

    Dec. 06, 2025

    Action Type Old Value New Value
    Added Reference https://git.kernel.org/stable/c/01d0d2b8b4e3cf2110baba9371c0c3d04ad5c77b
    Added Reference https://git.kernel.org/stable/c/18c3fa7a7fdbb4d21dafc8a7710ae2c1680930f6
    Added Reference https://git.kernel.org/stable/c/372ae77cf11d11fb118cbe2d37def9dd5f826abd
    Added Reference https://git.kernel.org/stable/c/3abebc503a5148072052c229c6b04b329a420ecd
    Added Reference https://git.kernel.org/stable/c/53af9c793f644d5841d84d8e0ad83bd7ab47f3e0
    Added Reference https://git.kernel.org/stable/c/7a6fb69bbcb21e9ce13bdf18c008c268874f0480
    Added Reference https://git.kernel.org/stable/c/7c183dc0af472dec33d2c0786a5e356baa8cad19
  • Initial Analysis by [email protected]

    Apr. 02, 2025

    Action Type Old Value New Value
    Added CPE Configuration OR *cpe:2.3:o:linux:linux_kernel:5.14:rc1:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:5.14:rc2:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 5.5 up to (excluding) 5.10.54 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 5.11 up to (excluding) 5.13.6 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 3.18 up to (excluding) 5.4.136
    Added Reference Type CVE: https://git.kernel.org/stable/c/8d7924ce85bae64e7a67c366c7c50840f49f3a62 Types: Patch
    Added Reference Type kernel.org: https://git.kernel.org/stable/c/8d7924ce85bae64e7a67c366c7c50840f49f3a62 Types: Patch
    Added Reference Type CVE: https://git.kernel.org/stable/c/8e9662fde6d63c78eb1350f6167f64c9d71a865b Types: Patch
    Added Reference Type kernel.org: https://git.kernel.org/stable/c/8e9662fde6d63c78eb1350f6167f64c9d71a865b Types: Patch
    Added Reference Type CVE: https://git.kernel.org/stable/c/cac71d27745f92ee13f0ecc668ffe151a4a9c9b1 Types: Patch
    Added Reference Type kernel.org: https://git.kernel.org/stable/c/cac71d27745f92ee13f0ecc668ffe151a4a9c9b1 Types: Patch
    Added Reference Type CVE: https://git.kernel.org/stable/c/f5051bcece50140abd1a11a2d36dc3ec5484fc32 Types: Patch
    Added Reference Type kernel.org: https://git.kernel.org/stable/c/f5051bcece50140abd1a11a2d36dc3ec5484fc32 Types: 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/8d7924ce85bae64e7a67c366c7c50840f49f3a62
    Added Reference https://git.kernel.org/stable/c/8e9662fde6d63c78eb1350f6167f64c9d71a865b
    Added Reference https://git.kernel.org/stable/c/cac71d27745f92ee13f0ecc668ffe151a4a9c9b1
    Added Reference https://git.kernel.org/stable/c/f5051bcece50140abd1a11a2d36dc3ec5484fc32
  • CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0

    Jul. 03, 2024

    Action Type Old Value New Value
    Added CWE CISA-ADP CWE-400
    Added CVSS V3.1 CISA-ADP AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
  • CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67

    May. 28, 2024

    Action Type Old Value New Value
  • CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67

    May. 21, 2024

    Action Type Old Value New Value
    Added Description In the Linux kernel, the following vulnerability has been resolved: net: sched: fix memory leak in tcindex_partial_destroy_work Syzbot reported memory leak in tcindex_set_parms(). The problem was in non-freed perfect hash in tcindex_partial_destroy_work(). In tcindex_set_parms() new tcindex_data is allocated and some fields from old one are copied to new one, but not the perfect hash. Since tcindex_partial_destroy_work() is the destroy function for old tcindex_data, we need to free perfect hash to avoid memory leak.
    Added Reference kernel.org https://git.kernel.org/stable/c/8d7924ce85bae64e7a67c366c7c50840f49f3a62 [No types assigned]
    Added Reference kernel.org https://git.kernel.org/stable/c/8e9662fde6d63c78eb1350f6167f64c9d71a865b [No types assigned]
    Added Reference kernel.org https://git.kernel.org/stable/c/cac71d27745f92ee13f0ecc668ffe151a4a9c9b1 [No types assigned]
    Added Reference kernel.org https://git.kernel.org/stable/c/f5051bcece50140abd1a11a2d36dc3ec5484fc32 [No types assigned]
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.
Vulnerability Scoring Details
Base CVSS Score: 7.5
Attack Vector
Attack Complexity
Privileges Required
User Interaction
Scope
Confidentiality Impact
Integrity Impact
Availability Impact