CVE-2026-29008

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Source
https://cve.org/CVERecord?id=CVE-2026-29008
Import Source
https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-29008.json
JSON Data
https://api.osv.dev/v1/vulns/CVE-2026-29008
Downstream
Published
2026-07-08T16:14:41Z
Modified
2026-08-12T03:51:10Z
Severity
  • 8.7 (High) CVSS_V4 - 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 CVSS Calculator
Summary
U-Boot 2026.04-rc3 Integer Underflow DoS via tcp_rx_state_machine()
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.

Database specific 
{
    "cna_assigner": "VulnCheck",
    "cwe_ids": [
        "CWE-191"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/29xxx/CVE-2026-29008.json"
}
References

Affected packages

Git / github.com/u-boot/u-boot

Affected ranges

Type
GIT
Repo
https://github.com/u-boot/u-boot
Events
Introduced
0 Unknown introduced commit / All previous commits are affected
Fixed
88dc2788777babfd6322fa655df549a019aa1e69
Introduced
aa4f687977a449686498236722ee5e93d8b39918
Last Affected
4f70106beafe30df8b0528a3d8b2543cd48fe241
Database specific
Show details 
{
    "cpe": [
        "cpe:2.3:a:denx:u-boot:*:*:*:*:*:*:*:*",
        "cpe:2.3:a:denx:u-boot:2026.04:rc1:*:*:*:*:*:*",
        "cpe:2.3:a:denx:u-boot:2026.04:rc2:*:*:*:*:*:*",
        "cpe:2.3:a:denx:u-boot:2026.04:rc3:*:*:*:*:*:*"
    ],
    "extracted_events": [
        {
            "introduced": "0"
        },
        {
            "fixed": "2026.04"
        },
        {
            "introduced": "2026.04-rc1"
        },
        {
            "last_affected": "2026.04-rc1"
        },
        {
            "introduced": "2026.04-rc2"
        },
        {
            "last_affected": "2026.04-rc2"
        },
        {
            "introduced": "2026.04-rc3"
        },
        {
            "last_affected": "2026.04-rc3"
        }
    ],
    "source": [
        "CPE_RANGE",
        "CPE_STRING"
    ]
}

Affected versions

2026.*
2026.04-rc1
2026.04-rc2
2026.04-rc3
v2026.*
v2026.04-rc1
v2026.04-rc2
v2026.04-rc3
v2026.04-rc4
v2026.04-rc5

Database specific

source 
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-29008.json"