🛡️ CVE-2026-29008 — u-boot

🟠 CVSS 7.5 — High ⚠️ Exploit Public CWE-191 NVD
7.5
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

U-Boot through 2026.04-rc3 contains an integer underflow vulnerability in the tcp_rx_state_machine() function (net/tcp.c) that allows a network-adjacent attacker to crash the bootloader by sending a malformed TCP SYN+ACK packet with a manipulated data offset field causing payload_len to become negative. When the TCP_SYN_SENT handler calls tcp_rx_user_data() without invoking tcp_seg_in_wnd() validation, the negative payload_len is implicitly converted to a large unsigned integer (e.g., 0xFFFFFFD8) and passed to memcpy() in store_block(), causing an immediate crash that prevents device boot and may enable memory corruption when CONFIG_LMB is disabled.

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is low, an attacker needs no privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality none, integrity none, availability high.

Weakness class

CVE-2026-29008 is classified as CWE-191: Integer Underflow. A subtraction drops below the minimum for the type and wraps, yielding an unexpectedly large value.

Affected software

CVE-2026-29008 is recorded against 1 package.

  • u-boot

Timeline and source

Published on 8 July 2026 and last revised on 22 July 2026. A public exploit is known to exist, which raises the urgency of patching considerably. Record sourced from NVD.

References

lists.denx.de
u-boot.org
www.vulncheck.com
y637f9qq2x.com

Details

Severity HIGH
CVSS Score 7.5
CVSS Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CWE CWE-191
Public Exploit ⚠️ Yes
Source NVD
Published 2026-07-08
Updated 2026-08-11
Modified 2026-07-22
Fix URL N/A

Affected Packages

Software From version Fixed in
u-boot — —

Similar Threats

Exploit Protection

Are you running u-boot?

CVE-2026-29008 carries CVSS 7.5 High rating and a public exploit already exists. BotEraser checks your installation against this and other known CVE records, and blocks IPs associated with exploit activity.

Check My Site For CVE-2026-29008 →

No credit card required  ·  Results in minutes

ⓘ Data Notice: The information presented above has been compiled from publicly available internet sources. Boteraser aggregates this data solely for informational purposes and does not independently classify, evaluate, or endorse any findings about the vulnerabilities listed. The accuracy and completeness of this information is the sole responsibility of the original publishers. Boteraser and its operators accept no liability for any decisions made based on this data.