8.7

CVE-2026-29008

Exploit

U-Boot 2026.04-rc3 Integer Underflow DoS via tcp_rx_state_machine()

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.
Daten sind bereitgestellt durch National Vulnerability Database (NVD)
Denx ≫ U-boot Version < 2026.04
Denx ≫ U-boot Version2026.04 Updaterc1
Denx ≫ U-boot Version2026.04 Updaterc2
Denx ≫ U-boot Version2026.04 Updaterc3
Zu dieser CVE wurde keine Warnung gefunden.
EPSS Metriken
Typ Quelle Score Percentile
EPSS FIRST.org 0.55% 0.428
CVSS Metriken
Quelle Base Score Exploit Score Impact Score Vector String
disclosure@vulncheck.com 8.7 0 0
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
disclosure@vulncheck.com 7.5 3.9 3.6
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CWE-191 Integer Underflow (Wrap or Wraparound)

The product subtracts one value from another, such that the result is less than the minimum allowable integer value, which produces a value that is not equal to the correct result.

https://lists.denx.de/pipermail/u-boot/2026-May/617853.html
Third Party Advisory
Mailing List
https://u-boot.org/
Product
https://www.vulncheck.com/advisories/u-boot-rc3-integer-underflow-dos-via-tcp-rx-state-machine
Third Party Advisory
Exploit
https://y637f9qq2x.com/posts/u-boot-tcp-nfs-vulns/
Third Party Advisory
Exploit