What’s Vulnerable › Vulnerabilities

CVE-2026-29007: U-Boot 2026.04-rc3 Out-of-Bounds Read in tcp_rx_state_machine via tcp.c

• Severity: medium (CVSS 5.3 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.7% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2026-07-08 · updated 2026-07-22
• Weakness: CWE-125

Description

U-Boot through 2026.04-rc3 contains an out-of-bounds read vulnerability in tcp_rx_state_machine() (net/tcp.c) when CONFIG_PROT_TCP is enabled, allowing remote attackers to read beyond TCP segment boundaries by crafting a malicious packet with a mismatched IP total length and TCP data offset field. Attackers can send a packet with an IP total length of 40 bytes and a TCP data offset claiming 60 bytes of header to cause 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 to disrupt TCP window calculations.

Affected products

• u-boot: before 2026.04; 2026.04-rc1, 2026.04-rc2, 2026.04-rc3 — fixed in 2026.04

How to fix

Upgrade to a fixed version: u-boot 2026.04. Check the vendor advisory for mitigations.

References

• https://lists.denx.de/pipermail/u-boot/2026-May/617853.html
• https://u-boot.org/
• https://www.vulncheck.com/advisories/u-boot-rc3-out-of-bounds-read-in-tcp-rx-state-machine-via-tcp-c
• https://y637f9qq2x.com/posts/u-boot-tcp-nfs-vulns/

Get alerted when CVE-2026-29007 or the next vulnerability affects your stack