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5.5
MEDIUM CVSS 3.1
CVE-2025-21765
ipv6: use RCU protection in ip6_default_advmss()
Description

In the Linux kernel, the following vulnerability has been resolved: ipv6: use RCU protection in ip6_default_advmss() ip6_default_advmss() needs rcu protection to make sure the net structure it reads does not disappear.

INFO

Published Date :

Feb. 27, 2025, 3:15 a.m.

Last Modified :

Nov. 3, 2025, 8:17 p.m.

Remotely Exploit :

No

Source :

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

The following products are affected by CVE-2025-21765 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
: Total Affected Vendor : 1 | Products : 1
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 MEDIUM [email protected]
Solution
Update the Linux kernel to a version with RCU protection for ip6_default_advmss().
  • Update the Linux kernel to the latest stable version.
  • Apply the patch for CVE-2025-21765.
  • Recompile and deploy the updated kernel.
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-2025-21765.

URL Resource
https://git.kernel.org/stable/c/28de355b63ad42309ed5a03ee7c436c90512265b Patch
https://git.kernel.org/stable/c/3c8ffcd248da34fc41e52a46e51505900115fc2a Patch
https://git.kernel.org/stable/c/4176a68b0db8fc74ac14fcd00ba8231371051dc2 Patch
https://git.kernel.org/stable/c/550ed693f47370502a71b85382e7f9e6417300b8 Patch
https://git.kernel.org/stable/c/713a40c892f40300d63691d9f85b2a23b48fe1e8 Patch
https://git.kernel.org/stable/c/78ad057472d8c76e0602402269222f9f9c698790 Patch
https://git.kernel.org/stable/c/84212387caadb211cd9dadd6fd5563bd37dc1f5e Patch
https://git.kernel.org/stable/c/d02f30d220ef9511568a48dba8a9004c65f8d904 Patch
https://lists.debian.org/debian-lts-announce/2025/03/msg00028.html
https://lists.debian.org/debian-lts-announce/2025/05/msg00030.html
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2025-21765 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-2025-21765 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-2025-21765 vulnerability anywhere in the article.

Results are limited to the first 20 news articles due to potential performance issues.

The following table lists the changes that have been made to the CVE-2025-21765 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 af854a3a-2127-422b-91ae-364da2661108

    Nov. 03, 2025

    Action Type Old Value New Value
    Added Reference https://lists.debian.org/debian-lts-announce/2025/03/msg00028.html
    Added Reference https://lists.debian.org/debian-lts-announce/2025/05/msg00030.html
  • Initial Analysis by [email protected]

    Oct. 28, 2025

    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 NVD-CWE-noinfo
    Added CPE Configuration OR *cpe:2.3:o:linux:linux_kernel:6.14:rc1:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.13 up to (excluding) 6.13.4 *cpe:2.3:o:linux:linux_kernel:6.14:rc2:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.2 up to (excluding) 6.6.79 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.7 up to (excluding) 6.12.16 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 5.11 up to (excluding) 5.15.179 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 2.6.26 up to (excluding) 5.4.291 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 5.5 up to (excluding) 5.10.235 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 5.16 up to (excluding) 6.1.129
    Added Reference Type kernel.org: https://git.kernel.org/stable/c/28de355b63ad42309ed5a03ee7c436c90512265b Types: Patch
    Added Reference Type kernel.org: https://git.kernel.org/stable/c/3c8ffcd248da34fc41e52a46e51505900115fc2a Types: Patch
    Added Reference Type kernel.org: https://git.kernel.org/stable/c/4176a68b0db8fc74ac14fcd00ba8231371051dc2 Types: Patch
    Added Reference Type kernel.org: https://git.kernel.org/stable/c/550ed693f47370502a71b85382e7f9e6417300b8 Types: Patch
    Added Reference Type kernel.org: https://git.kernel.org/stable/c/713a40c892f40300d63691d9f85b2a23b48fe1e8 Types: Patch
    Added Reference Type kernel.org: https://git.kernel.org/stable/c/78ad057472d8c76e0602402269222f9f9c698790 Types: Patch
    Added Reference Type kernel.org: https://git.kernel.org/stable/c/84212387caadb211cd9dadd6fd5563bd37dc1f5e Types: Patch
    Added Reference Type kernel.org: https://git.kernel.org/stable/c/d02f30d220ef9511568a48dba8a9004c65f8d904 Types: Patch
  • CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67

    Mar. 13, 2025

    Action Type Old Value New Value
    Added Reference https://git.kernel.org/stable/c/28de355b63ad42309ed5a03ee7c436c90512265b
    Added Reference https://git.kernel.org/stable/c/78ad057472d8c76e0602402269222f9f9c698790
    Added Reference https://git.kernel.org/stable/c/d02f30d220ef9511568a48dba8a9004c65f8d904
  • New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67

    Feb. 27, 2025

    Action Type Old Value New Value
    Added Description In the Linux kernel, the following vulnerability has been resolved: ipv6: use RCU protection in ip6_default_advmss() ip6_default_advmss() needs rcu protection to make sure the net structure it reads does not disappear.
    Added Reference https://git.kernel.org/stable/c/3c8ffcd248da34fc41e52a46e51505900115fc2a
    Added Reference https://git.kernel.org/stable/c/4176a68b0db8fc74ac14fcd00ba8231371051dc2
    Added Reference https://git.kernel.org/stable/c/550ed693f47370502a71b85382e7f9e6417300b8
    Added Reference https://git.kernel.org/stable/c/713a40c892f40300d63691d9f85b2a23b48fe1e8
    Added Reference https://git.kernel.org/stable/c/84212387caadb211cd9dadd6fd5563bd37dc1f5e
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: 5.5
Attack Vector
Attack Complexity
Privileges Required
User Interaction
Scope
Confidentiality Impact
Integrity Impact
Availability Impact