CVE-2024-35839
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.
Does this matter?
Lower severity and a low EPSS score (0.22%). Track it; it rarely justifies an emergency change on its own.
Description
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 3.1
- 5.5 MEDIUMCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- EPSS
- 0.22% probability · 13th percentile
- CISA KEV
- Not listed
- Affected
- linux/linux kernel
- Source
- 416baaa9-dc9f-4396-8d5f-8c081fb06d67
References
- https://git.kernel.org/stable/c/544add1f1cfb78c3dfa3e6edcf4668f6be5e730cPatch
- https://git.kernel.org/stable/c/7ae19ee81ca56b13c50a78de6c47d5b8fdc9d97bPatch
- https://git.kernel.org/stable/c/9325e3188a9cf3f69fc6f32af59844bbc5b90547Patch
- https://git.kernel.org/stable/c/9874808878d9eed407e3977fd11fee49de1e1d86Patch
- https://git.kernel.org/stable/c/544add1f1cfb78c3dfa3e6edcf4668f6be5e730cPatch
- https://git.kernel.org/stable/c/7ae19ee81ca56b13c50a78de6c47d5b8fdc9d97bPatch
- https://git.kernel.org/stable/c/9325e3188a9cf3f69fc6f32af59844bbc5b90547Patch
- https://git.kernel.org/stable/c/9874808878d9eed407e3977fd11fee49de1e1d86Patch
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.