CVE-2024-35839 Affecting kernel-modules-extra-common package, versions <0:6.1.75-99.163.amzn2023


Severity

Recommended
high

Based on Amazon Linux security rating.

Threat Intelligence

EPSS
0.05% (18th percentile)

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  • Snyk IDSNYK-AMZN2023-KERNELMODULESEXTRACOMMON-8494422
  • published11 Dec 2024
  • disclosed17 May 2024

Introduced: 17 May 2024

CVE-2024-35839  (opens in a new tab)

How to fix?

Upgrade Amazon-Linux:2023 kernel-modules-extra-common to version 0:6.1.75-99.163.amzn2023 or higher.
This issue was patched in ALAS2023-2024-519.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-modules-extra-common package and not the kernel-modules-extra-common package as distributed by Amazon-Linux. See How to fix? for Amazon-Linux:2023 relevant fixed versions and status.

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

netfilter: bridge: replace physindev with physinif in nf_bridge_info

An skb can be added to a neigh->arp_queue while waiting for an arp reply. Where original skb's skb->dev can be different to neigh's neigh->dev. For instance in case of bridging dnated skb from one veth to another, the skb would be added to a neigh->arp_queue of the bridge.

As skb->dev can be reset back to nf_bridge->physindev and used, and as there is no explicit mechanism that prevents this physindev from been freed under us (for instance neigh_flush_dev doesn't cleanup skbs from different device's neigh queue) we can crash on e.g. this stack:

arp_process neigh_update skb = __skb_dequeue(&neigh->arp_queue) neigh_resolve_output(..., skb) ... br_nf_dev_xmit br_nf_pre_routing_finish_bridge_slow skb->dev = nf_bridge->physindev br_handle_frame_finish

Let's use plain ifindex instead of net_device link. To peek into the original net_device we will use dev_get_by_index_rcu(). Thus either we get device and are safe to use it or we don't get it and drop skb.

CVSS Scores

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