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TI-2026-23176 Aliases CVE-2026-29008GHSA-3qwj-q697-4ppr

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

Priority MEDIUM 45CWE-191Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Attack requirements
None
Impact type
Denial of service
Confidentiality · integrity · availability
None · None · High
Fix status
No fix listed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-191 and the CVSS impact.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00706 53rd percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by the CNA and NVD
Fix No fix listed No fixed version in the sources yet

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
Yes
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
u-bootu-bootup to 2026.04-rc3—No fix listedCNA
  • u-boot Vendoru-boot Affected up to 2026.04-rc3 Fixed in — No fix listed CNA

CPE configurations NVD · 4

CPEVersionsRoleVendor
cpe:2.3:a:denx:u-boot:*:*:*:*:*:*:*:*before 2026.04Vulnerableu-boot
cpe:2.3:a:denx:u-boot:2026.04:rc1:*:*:*:*:*:*2026.04 rc1Vulnerableu-boot
cpe:2.3:a:denx:u-boot:2026.04:rc2:*:*:*:*:*:*2026.04 rc2Vulnerableu-boot
cpe:2.3:a:denx:u-boot:2026.04:rc3:*:*:*:*:*:*2026.04 rc3Vulnerableu-boot
  • cpe:2.3:a:denx:u-boot:*:*:*:*:*:*:*:* Versions before 2026.04 Vulnerable ·u-boot
  • cpe:2.3:a:denx:u-boot:2026.04:rc1:*:*:*:*:*:* Versions 2026.04 rc1 Vulnerable ·u-boot
  • cpe:2.3:a:denx:u-boot:2026.04:rc2:*:*:*:*:*:* Versions 2026.04 rc2 Vulnerable ·u-boot
  • cpe:2.3:a:denx:u-boot:2026.04:rc3:*:*:*:*:*:* Versions 2026.04 rc3 Vulnerable ·u-boot

Remediation

No fixed version listed by the sources yet.

Vendor assessments

Red Hat

Red Hat's page for this CVE →

Not affected: 1 product
  • Red Hat

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-29008
  2. 2026-10-03 Alias added: GHSA-3qwj-q697-4ppr

References

Exploit 1

Advisory 1

Other 1

  • TI-2022-02168 Unchecked Download size in Uboot CVSS 3.1HIGH 7.7
  • TI-2025-28794 A lack of signature verification in the bootloader of DENX Software Engineering Das… CVSS 3.1MEDIUM 6.5
  • TI-2020-06770 In Das U-Boot through 2020.01, a double free has been found in the cmd/gpt.c… CVSS 3.1CRITICAL 9.8
  • TI-2022-12898 nfs_lookup_reply in net/nfs.c in Das U-Boot through 2022.04 (and through 2022.07-rc2) has… CVSS 3.1CRITICAL 9.8
  • TI-2019-10569 An issue was discovered in Das U-Boot through 2019.07. CVSS 3.0CRITICAL 9.8
  • TI-2019-10568 An issue was discovered in Das U-Boot through 2019.07. CVSS 3.0CRITICAL 9.8
See all 48 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences