CVE-2025-21759
ipv6: mcast: extend RCU protection in igmp6_send()
Description
In the Linux kernel, the following vulnerability has been resolved: ipv6: mcast: extend RCU protection in igmp6_send() igmp6_send() can be called without RTNL or RCU being held. Extend RCU protection so that we can safely fetch the net pointer and avoid a potential UAF. Note that we no longer can use sock_alloc_send_skb() because ipv6.igmp_sk uses GFP_KERNEL allocations which can sleep. Instead use alloc_skb() and charge the net->ipv6.igmp_sk socket under RCU protection.
INFO
Published Date :
Feb. 27, 2025, 3:15 a.m.
Last Modified :
Oct. 3, 2026, 11:17 a.m.
Remotely Exploit :
No
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | HIGH | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | ||||
| CVSS 3.1 | HIGH | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 |
Solution
- Update the Linux kernel to a patched version.
- Apply the necessary security updates.
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-2025-21759.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2025-21759 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-2025-21759
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-2025-21759 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2025-21759 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
Oct. 03, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H Added Affected Affected value modified. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2025/21xxx/CVE-2025-21759.json">CVE-2025-21759</a> Added Reference https://git.kernel.org/stable/c/087c1faa594fa07a66933d750c0b2610aa1a2946 Added Reference https://git.kernel.org/stable/c/0bf8e2f3768629d437a32cb824149e6e98254381 Added Reference https://git.kernel.org/stable/c/638e8fe3563a82f298fe537a28d5342a97278cf1 Added Reference https://git.kernel.org/stable/c/6901bbb169e3add6c037218d996790cef6b3d650 Added Reference https://git.kernel.org/stable/c/7e0a818ecc4d62e7fb668ea02de0bfe8ba0b7dff Added Reference https://git.kernel.org/stable/c/81b25a07ebf53f9ef4ca8f3d96a8ddb94561dd5a Added Reference https://git.kernel.org/stable/c/8e92d6a413feaf968a33f0b439ecf27404407458 Removed Reference https://git.kernel.org/stable/c/087c1faa594fa07a66933d750c0b2610aa1a2946 Removed Reference https://git.kernel.org/stable/c/0bf8e2f3768629d437a32cb824149e6e98254381 Removed Reference https://git.kernel.org/stable/c/81b25a07ebf53f9ef4ca8f3d96a8ddb94561dd5a Removed Reference https://git.kernel.org/stable/c/8e92d6a413feaf968a33f0b439ecf27404407458 Removed Reference Type https://git.kernel.org/stable/c/087c1faa594fa07a66933d750c0b2610aa1a2946 Types: Patch Removed Reference Type https://git.kernel.org/stable/c/0bf8e2f3768629d437a32cb824149e6e98254381 Types: Patch Removed Reference Type https://git.kernel.org/stable/c/81b25a07ebf53f9ef4ca8f3d96a8ddb94561dd5a Types: Patch Removed Reference Type https://git.kernel.org/stable/c/8e92d6a413feaf968a33f0b439ecf27404407458 Types: Patch -
CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Jun. 17, 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': 'b8ad0cbc58f703972e9e37c4e2a8081dd7e6a551', 'lessThan': '81b25a07ebf53f9ef4ca8f3d96a8ddb94561dd5a', 'versionType': 'git'}, {'status': 'affected', 'version': 'b8ad0cbc58f703972e9e37c4e2a8081dd7e6a551', 'lessThan': '0bf8e2f3768629d437a32cb824149e6e98254381', 'versionType': 'git'}, {'status': 'affected', 'version': 'b8ad0cbc58f703972e9e37c4e2a8081dd7e6a551', 'lessThan': '8e92d6a413feaf968a33f0b439ecf27404407458', 'versionType': 'git'}, {'status': 'affected', 'version': 'b8ad0cbc58f703972e9e37c4e2a8081dd7e6a551', 'lessThan': '087c1faa594fa07a66933d750c0b2610aa1a2946', 'versionType': 'git'}], 'programFiles': ['net/ipv6/mcast.c'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '2.6.26'}, {'status': 'unaffected', 'version': '0', 'lessThan': '2.6.26', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '6.6.79', 'versionType': 'semver', 'lessThanOrEqual': '6.6.*'}, {'status': 'unaffected', 'version': '6.12.16', 'versionType': 'semver', 'lessThanOrEqual': '6.12.*'}, {'status': 'unaffected', 'version': '6.13.4', 'versionType': 'semver', 'lessThanOrEqual': '6.13.*'}, {'status': 'unaffected', 'version': '6.14', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['net/ipv6/mcast.c'], 'defaultStatus': 'affected'}] -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jun. 17, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2025-21759', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'no'}, {'technicalImpact': 'total'}], 'version': '2.0.3', 'timestamp': '2025-02-27T17:57:46.460072Z'} -
Initial Analysis by [email protected]
Mar. 24, 2025
Action Type Old Value New Value 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) 6.7 up to (excluding) 6.12.16 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 2.6.26 up to (excluding) 6.6.79 Added Reference Type kernel.org: https://git.kernel.org/stable/c/087c1faa594fa07a66933d750c0b2610aa1a2946 Types: Patch Added Reference Type kernel.org: https://git.kernel.org/stable/c/0bf8e2f3768629d437a32cb824149e6e98254381 Types: Patch Added Reference Type kernel.org: https://git.kernel.org/stable/c/81b25a07ebf53f9ef4ca8f3d96a8ddb94561dd5a Types: Patch Added Reference Type kernel.org: https://git.kernel.org/stable/c/8e92d6a413feaf968a33f0b439ecf27404407458 Types: Patch -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Feb. 27, 2025
Action Type Old Value New Value Added CVSS V3.1 AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H Added CWE CWE-416 -
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: mcast: extend RCU protection in igmp6_send() igmp6_send() can be called without RTNL or RCU being held. Extend RCU protection so that we can safely fetch the net pointer and avoid a potential UAF. Note that we no longer can use sock_alloc_send_skb() because ipv6.igmp_sk uses GFP_KERNEL allocations which can sleep. Instead use alloc_skb() and charge the net->ipv6.igmp_sk socket under RCU protection. Added Reference https://git.kernel.org/stable/c/087c1faa594fa07a66933d750c0b2610aa1a2946 Added Reference https://git.kernel.org/stable/c/0bf8e2f3768629d437a32cb824149e6e98254381 Added Reference https://git.kernel.org/stable/c/81b25a07ebf53f9ef4ca8f3d96a8ddb94561dd5a Added Reference https://git.kernel.org/stable/c/8e92d6a413feaf968a33f0b439ecf27404407458