CVE-2026-88834 Busybox: busybox: httpd user existence oracle in non-default shadow-disabled builds
An attacker can enumerate valid usernames in BusyBox httpd when system password authentication is enabled in non-default builds.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-88834?
CVE-2026-88834 is a low-severity vulnerability in Red Hat Hardened Images, published on 13 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
A flaw was found in BusyBox's httpd web server. When configured with system password authentication, a user existence oracle may exist in certain build configurations. An attacker could distinguish existing from non-existing usernames by observing authentication failure behavior. Impact is limited to username enumeration and requires non-default compile options or uncommon password file states; default BusyBox builds with shadow password support are not affected.
Weakness: CWE-203
Which versions are affected by CVE-2026-88834?
How do I fix CVE-2026-88834?
Apply the vendor's patch.
Is CVE-2026-88834 being exploited?
There is no known exploitation of CVE-2026-88834 in the wild and no public exploit code.
Sources
Also known as AZL-108318, BELL-CVE-2026-88834, DEBIAN-CVE-2026-88834, GHSA-g83p-qwfp-8p23, UBUNTU-CVE-2026-88834.