Linux Kernel up to 6.8.4 on TCP net/smc/af_smc.c inet_csk_clear_xmit_timers privilege escalation

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Summaryinfo

A vulnerability, which was classified as problematic, was found in Linux Kernel up to 6.8.4 on TCP. The impacted element is the function inet_csk_clear_xmit_timers of the file net/smc/af_smc.c. Executing a manipulation can lead to an unknown weakness. This vulnerability is tracked as CVE-2024-35910. No exploit exists. You should upgrade the affected component.

Detailsinfo

A vulnerability has been found in Linux Kernel up to 6.8.4 on TCP and classified as problematic. This vulnerability affects the function inet_csk_clear_xmit_timers of the file net/smc/af_smc.c. The impact remains unknown. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: tcp: properly terminate timers for kernel sockets We had various syzbot reports about tcp timers firing after the corresponding netns has been dismantled. Fortunately Josef Bacik could trigger the issue more often, and could test a patch I wrote two years ago. When TCP sockets are closed, we call inet_csk_clear_xmit_timers() to 'stop' the timers. inet_csk_clear_xmit_timers() can be called from any context, including when socket lock is held. This is the reason it uses sk_stop_timer(), aka del_timer(). This means that ongoing timers might finish much later. For user sockets, this is fine because each running timer holds a reference on the socket, and the user socket holds a reference on the netns. For kernel sockets, we risk that the netns is freed before timer can complete, because kernel sockets do not hold reference on the netns. This patch adds inet_csk_clear_xmit_timers_sync() function that using sk_stop_timer_sync() to make sure all timers are terminated before the kernel socket is released. Modules using kernel sockets close them in their netns exit() handler. Also add sock_not_owned_by_me() helper to get LOCKDEP support : inet_csk_clear_xmit_timers_sync() must not be called while socket lock is held. It is very possible we can revert in the future commit 3a58f13a881e ("net: rds: acquire refcount on TCP sockets") which attempted to solve the issue in rds only. (net/smc/af_smc.c and net/mptcp/subflow.c have similar code) We probably can remove the check_net() tests from tcp_out_of_resources() and __tcp_close() in the future.

The advisory is available at git.kernel.org. This vulnerability was named CVE-2024-35910 since 05/17/2024. Technical details are known, but there is no available exploit.

The vulnerability scanner Nessus provides a plugin with the ID 209785 (EulerOS Virtualization 2.12.0 : kernel (EulerOS-SA-2024-2781)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 4.19.312, 5.4.274, 5.10.215, 5.15.154, 6.1.85, 6.6.26 or 6.8.5 eliminates this vulnerability. Applying the patch 93f0133b9d58/44e62f5d3567/e3e27d2b446d/2e43d8eba6ed/91b243de910a/c1ae4d1e76ea/899265c1389f/151c9c724d05 is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the databases at Tenable (209785) and CERT Bund (WID-SEC-2025-1439). If you want to get best quality of vulnerability data, you may have to visit VulDB.

Affected

  • SUSE Linux
  • Dell Secure Connect Gateway

Productinfo

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Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.7
VulDB Meta Temp Score: 5.6

VulDB Base Score: 5.5
VulDB Temp Score: 5.3
VulDB Vector: 🔍
VulDB Reliability: 🔍

NVD Base Score: 5.8
NVD Vector: 🔍

CNA Base Score: 5.8
CNA Vector: 🔍

CVSSv2info

AVACAuCIA
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VulDB Base Score: 🔍
VulDB Temp Score: 🔍
VulDB Reliability: 🔍

Exploitinginfo

Class: Privilege escalation
CWE: Unknown
CAPEC: 🔍
ATT&CK: 🔍

Physical: Partially
Local: Yes
Remote: Partially

Availability: 🔍
Status: Not defined

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

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Nessus ID: 209785
Nessus Name: EulerOS Virtualization 2.12.0 : kernel (EulerOS-SA-2024-2781)

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔍

Upgrade: Kernel 4.19.312/5.4.274/5.10.215/5.15.154/6.1.85/6.6.26/6.8.5
Patch: 93f0133b9d58/44e62f5d3567/e3e27d2b446d/2e43d8eba6ed/91b243de910a/c1ae4d1e76ea/899265c1389f/151c9c724d05

Timelineinfo

05/17/2024 🔍
05/19/2024 +2 days 🔍
05/19/2024 +0 days 🔍
01/21/2026 +611 days 🔍

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2024-35910 (🔍)
GCVE (CVE): GCVE-0-2024-35910
GCVE (VulDB): GCVE-100-265162
CERT Bund: WID-SEC-2025-1439 - Dell Secure Connect Gateway: Mehrere Schwachstellen ermöglichen nicht spezifizierten Angriff

Entryinfo

Created: 05/19/2024 13:10
Updated: 01/21/2026 00:31
Changes: 05/19/2024 13:10 (58), 10/28/2024 05:02 (2), 10/30/2024 03:25 (12), 12/17/2025 04:52 (11), 01/21/2026 00:31 (7)
Complete: 🔍
Cache ID: 216::103

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