AUGUST 24, 2026
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Case File

CVE-2026-29008

HIGH · CVSS 7.5 EPSS 0.55%

Source: NVD + CISA KEV + EPSS · Published 2026-07-08 · Last synced 2026-08-07

CyberRota Analysis

AI-Generated

The vulnerability affects the U-Boot bootloader, specifically in the tcp_rx_state_machine() function, where an integer underflow can be exploited by a network-adjacent attacker. By sending a specially crafted TCP SYN+ACK packet, the attacker can trigger a crash of the bootloader, potentially leading to device boot failure and memory corruption if certain configurations are disabled. Organizations utilizing U-Boot in their embedded systems should prioritize patching this vulnerability to mitigate the risk of denial-of-service attacks and ensure system stability.

CVE
CVE-2026-29008
Severity
HIGH
CVSS
7.5
EPSS
0.55%

Original NVD 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.

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