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CVE-2024-49940

7.8 · HIGH
Published Oct 21, 2024 linux EPSS 0.24% (15th pctl)

Overview

CVE-2024-49940 is a high-severity vulnerability affecting linux linux_kernel. It was published on October 21, 2024 and has a CVSS 3.1 base score of 7.8 (HIGH).

This vulnerability has a CVSS 3.1 base score of 7.8, rated HIGH. It requires local or adjacent network access to exploit. Some level of privileges is required for exploitation.

Technical Description

In the Linux kernel, the following vulnerability has been resolved:

l2tp: prevent possible tunnel refcount underflow

When a session is created, it sets a backpointer to its tunnel. When

the session refcount drops to 0, l2tp_session_free drops the tunnel

refcount if session->tunnel is non-NULL. However, session->tunnel is

set in l2tp_session_create, before the tunnel refcount is incremented

by l2tp_session_register, which leaves a small window where

session->tunnel is non-NULL when the tunnel refcount hasn't been

bumped.

Moving the assignment to l2tp_session_register is trivial but

l2tp_session_create calls l2tp_session_set_header_len which uses

session->tunnel to get the tunnel's encap. Add an encap arg to

l2tp_session_set_header_len to avoid using session->tunnel.

If l2tpv3 sessions have colliding IDs, it is possible for

l2tp_v3_session_get to race with l2tp_session_register and fetch a

session which doesn't yet have session->tunnel set. Add a check for

this case.

Remediation

Check the references section for vendor advisories and patches from linux. Update linux_kernel to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

Affected Products

Vendor Product Versions Status
linux linux_kernel >= 0, < 6.11.3 Affected

Frequently Asked Questions

What is CVE-2024-49940?

CVE-2024-49940 is a high-severity vulnerability affecting linux linux_kernel. It was published on October 21, 2024 and has a CVSS 3.1 base score of 7.8 (HIGH).

How severe is CVE-2024-49940?

This vulnerability has a CVSS 3.1 base score of 7.8, rated HIGH. It requires local or adjacent network access to exploit. Some level of privileges is required for exploitation.

How do I fix or remediate CVE-2024-49940?

Check the references section for vendor advisories and patches from linux. Update linux_kernel to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

How can CyberStrike help with CVE-2024-49940?

CyberStrike's AI-powered security agents can automatically detect CVE-2024-49940 across your infrastructure using autonomous pentesting, DAST scanning, and HackBrowser. The platform continuously monitors for known vulnerabilities and provides actionable remediation guidance prioritized by real-world exploitability.