Out-of-bounds Read in Denx U-Boot
CVE-2026-29007
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.
Vulnerability class: Buffer Overflow
Published · last modified .
CVSS v3 metric
CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L.
EPSS exploit prediction
EPSS: 0.007 (50.4th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 50th percentile — 50.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.007 · newest: 0.007 · change: 0.000
Affected products
- Denx U-Boot — versions 2026.04
- U-Boot — versions 0
Weakness classification (CWE)
References
- lists.denx.de/pipermail/u-boot/2026-May/617853.html (issue-tracking, Mailing List, Third Party Advisory)
- u-boot.org/ (Product, product)
- www.vulncheck.com/advisories/u-boot-rc3-out-of-bounds-read-in-tcp-rx-state-mach… (Exploit, Third Party Advisory, third-party-advisory)
- y637f9qq2x.com/posts/u-boot-tcp-nfs-vulns/ (Exploit, technical-description, Third Party Advisory, exploit)
Frequently asked questions
- What is CVE-2026-29007?
- CVE-2026-29007 is a medium-severity vulnerability in Denx U-Boot, classified under Out-of-bounds Read. CVSS score: 5.3/10. Published 2026-07-08.
- How severe is CVE-2026-29007?
- Medium severity. CVSS v3 base score is 5.3 out of 10.