High severity · published Sep 29, 2026
CVE-2026-71971
U-Boot before 2026.10-rc3 Out-of-Bounds Write in IP Fragment Reassembly
8.2
CVSS
0.4%
EPSS
No
On KEV
Description
U-Boot before 2026.10-rc3 with CONFIG_IP_DEFRAG enabled contains an out-of-bounds write vulnerability in the __net_defragment() function in net/net.c. Remote attackers can send a crafted IP fragment with non-zero offset and More-Fragments flag set during netboot to corrupt adjacent memory and crash the bootloader.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
Low
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 31% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
UB
u-boot · u-boot
before 2026.10-rc3 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-71971
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-71971
patch
https://github.com/u-boot/u-boot/commit/04ca915d5bf39dda5d1bce62d04d2b59d293c5b9
technical-description
https://github.com/u-boot/u-boot/blob/v2026.07/net/net.c#L975
product
https://github.com/u-boot/u-boot
third-party-advisory
https://www.vulncheck.com/advisories/u-boot-before-2026.10-rc3-out-of-bounds-write-in-ip-fragment-reassembly
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