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Fencer Intel
high 8.2

CVE-2026-71971 json

U-Boot before 2026.10-rc3 Out-of-Bounds Write in IP Fragment Reassembly

published last mo. modified last mo. also EUVD-2026-89429

cvss
8.2
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 31%
public exploits
0
none known

Summary

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.

Patch / fix

  • u-boot u-boot 2026.10-rc3
  • u-boot Ubuntu 22.04 LTS 2022.01+dfsg-2ubuntu2.8
  • u-boot Ubuntu 24.04 LTS 2025.10-0ubuntu0.24.04.3
  • u-boot Ubuntu 26.10 2025.10-0ubuntu5
  • u-boot Ubuntu 26.04 LTS 2025.10-0ubuntu2.1
  • u-boot Ubuntu Pro 16.04 LTS 2016.01+dfsg1-2ubuntu5+esm1
  • u-boot Ubuntu Pro 18.04 LTS 2020.10+dfsg-1ubuntu0~18.04.3+esm1
  • u-boot Ubuntu Pro 20.04 LTS 2021.01+dfsg-3ubuntu0~20.04.6+esm1

ubuntu advisories UBUNTU-CVE-2026-71971

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

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CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
last mo.

Exploit prediction

0.38% chance of exploitation in the next 30 days, higher than 31% of all scored CVEs (FIRST EPSS, 2026-11-11).

CVSS scores

assigned by version score vector
CNA 4.0 8.8 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:H/SC:N/SI:N/SA:N
CNA 3.1 8.2 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H
CNA 4.0 8.8 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/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

Affected products

  • u-boot u-boot

Classification

Weakness

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.