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Fencer Vulns
high 8.2

CVE-2026-74221 json

U-Boot before 2026.10-rc5 Buffer Overflow via NFS READLINK

published 2026-09-29 40 d ago modified 2026-09-30 39 d ago also EUVD-2026-89434

cvss
8.2
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 27%
public exploits
0
none known

Summary

U-Boot before 2026.10-rc5 contains a buffer overflow in nfs_readlink_reply() function in net/nfs-common.c when processing NFS server responses. A malicious NFS server can send crafted READLINK replies with negative or oversized symlink length values to corrupt memory and crash the bootloader.

Patch / fix

  • u-boot u-boot 2026.10-rc5
  • u-boot Ubuntu 22.04 LTS 2022.01+dfsg-2ubuntu2.9
  • u-boot Ubuntu 24.04 LTS 2025.10-0ubuntu0.24.04.4
  • u-boot Ubuntu 26.10 2025.10-0ubuntu6
  • u-boot Ubuntu 26.04 LTS 2025.10-0ubuntu2.2
  • u-boot Ubuntu Pro 16.04 LTS 2016.01+dfsg1-2ubuntu5+esm2
  • u-boot Ubuntu Pro 18.04 LTS 2020.10+dfsg-1ubuntu0~18.04.3+esm2
  • u-boot Ubuntu Pro 20.04 LTS 2021.01+dfsg-3ubuntu0~20.04.6+esm2

ubuntu advisories UBUNTU-CVE-2026-74221

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

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
39 d ago

Exploit prediction

0.34% chance of exploitation in the next 30 days, higher than 27% of all scored CVEs (FIRST EPSS, 2026-11-08).

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
  • CWE-195 Signed to Unsigned Conversion Error

References

Sources

Fencer Vulns 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.