CVE-2026-29009Public exploit

Pre-OS code execution via unchecked symlink appends

Published Jul 8, 2026 · Updated Jul 8, 2026

Buffer overflow in U-Boot before 2026.07-rc2 allows remote attackers to execute code through crafted NFS READLINK replies. nfs_readlink_reply() appends each relative symlink target to the 2048-byte nfs_path_buff without checking the accumulated path length, overwriting adjacent NFS state. Exploitation requires CONFIG_CMD_NFS and an NFS boot in which a malicious server controls repeated symlink resolutions.

CVSS severity8.8
High
EPSS probability0.74%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Buffer overflow in U-Boot before 2026.07-rc2 allows remote attackers to execute code through crafted NFS READLINK replies. nfs_readlink_reply() appends each relative symlink target to the 2048-byte nfs_path_buff without checking the accumulated path length, overwriting adjacent NFS state. Exploitation requires CONFIG_CMD_NFS and an NFS boot in which a malicious server controls repeated symlink resolutions.

The record

CVE
CVE-2026-29009
Published
Jul 8, 2026
Updated
Jul 8, 2026
Vendor
DENX Software Engineering GmbH
Product
U-Boot
Classifications
CWE-120, T1203
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 8, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 8, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <=2026.04-rc3

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

DENX Software Engineering GmbH · U-Bootversion=0 <=2026.04-rc3

Published CVSS scores

8.8VulnCheckCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:H/SC:N/SI:N/SA:N
9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
8.2VulnCheckCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectoradjacent
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-120Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
T1203Exploitation for Client Execution

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo