Improper Authorization in fwupd - #VU140589
Published: July 26, 2026 / Updated: July 31, 2026
Vulnerability identifier: #VU140589
CSH Severity: Low
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear
CVE-ID: N/A
CWE-ID: CWE-285
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Affected software:
fwupd
fwupd
Detailed vulnerability description
The vulnerability allows a remote user to install a downgrade as a trusted update without a prompt.
The vulnerability exists due to improper access control in the D-Bus install path when consuming unsigned metainfo before trusted metadata validation. A remote user can submit a crafted archive with a modified release version field to install a downgrade as a trusted update without a prompt.
Exploitation requires an active seat session with the unmodified auto-launched daemon, upstream polkit policy, and OnlyTrusted enabled.
Remediation
Install security update from vendor's website.