CVE-2026-53014

Description

In the Linux kernel, the following vulnerability has been resolved: net/sched: act_mirred: fix wrong device for mac_header_xmit check in tcf_blockcast_redir In tcf_blockcast_redir(), when iterating block ports to redirect packets to multiple devices, the mac_header_xmit flag is queried from the wrong device. The loop sends to dev_prev but queries dev_is_mac_header_xmit(dev) — which is the NEXT device in the iteration, not the one being sent to. This causes tcf_mirred_to_dev() to make incorrect decisions about whether to push or pull the MAC header. When the block contains mixed device types (e.g., an ethernet veth and a tunnel device), intermediate devices get the wrong mac_header_xmit flag, leading to skb header corruption. In the worst case, skb_push_rcsum with an incorrect mac_len can exhaust headroom and panic. The last device in the loop is handled correctly (line 365-366 uses dev_is_mac_header_xmit(dev_prev)), confirming this is a copy-paste oversight for the intermediate devices. Fix by using dev_prev instead of dev for the mac_header_xmit query, consistent with the device actually being sent to.

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

References

• https://git.kernel.org/stable/c/8fda5174286119addd28473fb2ec5bdf521c05a8 ↗
• https://git.kernel.org/stable/c/7db3e4e03032261b1b519341123fc30d995478ca ↗
• https://git.kernel.org/stable/c/4764953c4b47585eb72797b216b63a831dc0c7e6 ↗
• https://git.kernel.org/stable/c/4510d140524ca7d6e772db962e013f26f09a63b1 ↗