{"id":"DEBIAN-CVE-2026-29008","details":"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.","modified":"2026-09-01T16:06:37.233712177Z","published":"2026-07-08T17:17:21.047Z","upstream":["CVE-2026-29008"],"references":[{"type":"ADVISORY","url":"https://security-tracker.debian.org/tracker/CVE-2026-29008"}],"affected":[{"package":{"name":"u-boot","ecosystem":"Debian:12","purl":"pkg:deb/debian/u-boot?arch=source&distro=bookworm"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2023.01+dfsg-2","2023.01+dfsg-2+deb12u1","2023.01+dfsg-2+deb12u2","2023.01+dfsg-2+deb12u3","2023.04+dfsg-1","2023.04~rc2+dfsg-1","2023.04~rc5+dfsg-1","2023.07+dfsg-1","2023.07~rc4+dfsg-1","2023.07~rc5+dfsg-1","2024.01+dfsg-1","2024.01+dfsg-2","2024.01+dfsg-3","2024.01+dfsg-4","2024.01+dfsg-5","2024.01+dfsg-6","2024.01+dfsg-7","2024.01~rc6+dfsg-1","2024.01~rc6+dfsg-2","2025.01-1","2025.01-2","2025.01-3","2025.01-3.1","2025.01-3.2"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2026-29008.json"}},{"package":{"name":"u-boot","ecosystem":"Debian:13","purl":"pkg:deb/debian/u-boot?arch=source&distro=trixie"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2025.01-3","2025.01-3+deb13u1","2025.01-3.1","2025.01-3.2"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2026-29008.json"}},{"package":{"name":"u-boot","ecosystem":"Debian:14","purl":"pkg:deb/debian/u-boot?arch=source&distro=forky"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2025.01-3","2025.01-3.1","2025.01-3.2"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2026-29008.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V4","score":"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"}]}