Security assessments indicate that CVE-2024-54680 presents a notable risk, potentially requiring prompt mitigation.
Status: Modified
Last updated: 🕕 10 Feb 2025, 18:15 UTC
Originally published on: 🕐 11 Jan 2025, 13:15 UTC
Time between publication and last update: 30 days
CVSS Release: version 3
nvd@nist.gov
Primary
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
CVE-2024-54680: In the Linux kernel, the following vulnerability has been resolved: smb: client: fix TCP timers deadlock after rmmod Commit ef7134c7fc48 ("smb: client: Fix use-after-free of network namespace.") fixed a netns UAF by manually enabled socket refcounting (sk->sk_net_refcnt=1 and sock_inuse_add(net, 1)). The reason the patch worked for that bug was because we now hold references to the netns (get_net_track() gets a ref internally) and they're properly released (internally, on __sk_destruct()), but only because sk->sk_net_refcnt was set. Problem: (this happens regardless of CONFIG_NET_NS_REFCNT_TRACKER and regardless if init_net or other) Setting sk->sk_net_refcnt=1 *manually* and *after* socket creation is not only out of cifs scope, but also technically wrong -- it's set conditionally based on user (=1) vs kernel (=0) sockets. And net/ implementations seem to base their user vs kernel space operations on it. e.g. upon TCP socket close, the TCP timers are not cleared because sk->sk_net_refcnt=1: (cf. commit 151c9c724d05 ("tcp: properly terminate timers for kernel sockets")) net/ipv4/tcp.c: void tcp_close(struct sock *sk, long timeout) { lock_sock(sk); __tcp_close(sk, timeout); release_sock(sk); if (!sk->sk_net_refcnt) inet_csk_clear_xmit_timers_sync(sk); sock_put(sk); } Which will throw a lockdep warning and then, as expected, deadlock on tcp_write_timer(). A way to reproduce this is by running the reproducer from ef7134c7fc48 and then 'rmmod cifs'. A few seconds later, the deadlock/lockdep warning shows up. Fix: We shouldn't mess with socket internals ourselves, so do not set sk_net_refcnt manually. Also change __sock_create() to sock_create_kern() for explicitness. As for non-init_net network namespaces, we deal with it the best way we can -- hold an extra netns reference for server->ssocket and drop it when it's released. This ensures that the netns still exists whenever we need to create/destroy server->ssocket, but is not directly tied to it.
The exploitability of CVE-2024-54680 depends on two key factors: attack complexity (the level of effort required to execute an exploit) and privileges required (the access level an attacker needs).
CVE-2024-54680 presents an accessible attack vector with minimal effort required. Restricting access controls and implementing security updates are critical to reducing exploitation risks.
A lower complexity and fewer privilege requirements make exploitation easier. Security teams should evaluate these aspects to determine the urgency of mitigation strategies, such as patch management and access control policies.
Attack Complexity (AC) measures the difficulty in executing an exploit. A high AC means that specific conditions must be met, making an attack more challenging, while a low AC means the vulnerability can be exploited with minimal effort.
Privileges Required (PR) determine the level of system access necessary for an attack. Vulnerabilities requiring no privileges are more accessible to attackers, whereas high privilege requirements limit exploitation to authorized users with elevated access.
Above is the CVSS Sub-score Breakdown for CVE-2024-54680, illustrating how Base, Impact, and Exploitability factors combine to form the overall severity rating. A higher sub-score typically indicates a more severe or easier-to-exploit vulnerability.
Below is the Impact Analysis for CVE-2024-54680, showing how Confidentiality, Integrity, and Availability might be affected if the vulnerability is exploited. Higher values usually signal greater potential damage.
The EPSS score estimates the probability that this vulnerability will be exploited in the near future.
EPSS Score: 0.042% (probability of exploit)
EPSS Percentile: 5.07%
(lower percentile = lower relative risk)
This vulnerability is less risky than approximately 94.93% of others.
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