CVE-2026-29007 u-boot CVE debrief

Who should care

Organizations using U-Boot firmware, especially versions up to 2026.04-rc3, should be aware of this vulnerability. This vulnerability could potentially allow attackers to disrupt TCP window calculations by corrupting connection state variables.

Technical summary

The vulnerability exists in the tcp_rx_state_machine() function in net/tcp.c of U-Boot. When CONFIG_PROT_TCP is enabled, an attacker can send a crafted packet with an IP total length of 40 bytes and a TCP data offset claiming 60 bytes of header. This causes tcp_parse_options() to read 40 bytes past the end of the TCP segment, potentially corrupting connection state variables such as rmt_win_scale and rmt_timestamp. This corruption can disrupt TCP window calculations.

Defensive priority

Medium priority should be given to patching this vulnerability, as it could potentially be used to disrupt TCP connections.

Recommended defensive actions

• Apply the official patch or update to a version of U-Boot that is not vulnerable.
• Implement network monitoring to detect potential exploitation attempts.
• Restrict access to the U-Boot configuration and limit the ability to send crafted packets to the system.
• Review compensating controls for exposed systems while remediation is scheduled and verified.
• Check relevant monitoring, detection, and logs for exposed assets that need extra review.
• Track exceptions, retest remediated assets, and close the item only after evidence is documented.
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up.

Evidence notes

The CVE record was published on 2026-07-08T17:17:20.907Z and was last modified on 2026-07-10T18:01:31.563Z. The NVD entry is currently Awaiting Analysis. The vulnerability was disclosed via multiple sources including the U-Boot mailing list and VulnCheck.

Official resources