User Existence Oracle Vulnerability in BusyBox Web Server by BusyBox
CVE-2026-88834

3.7LOW

Key Information:

Vendor

Red Hat
Status
Red Hat Hardened Images
Vendor
CVE Published:
13 October 2026

What is CVE-2026-88834?

A vulnerability has been identified in the BusyBox httpd web server related to user existence oracle through improper handling of authentication failures. When configured with system password authentication and under certain build configurations, an attacker may exploit the authentication failure behavior to differentiate between existing and non-existing usernames. This technique relies on specific compile options or unique password file states, and generally does not affect default BusyBox builds that come with shadow password support. Users are encouraged to review their configurations to mitigate the risk of username enumeration.

References

https://access.redhat.com/security/cve/CVE-2026-88834
vdb-entryx_refsource_REDHAT
https://bugzilla.redhat.com/show_bug.cgi?id=2531348
issue-trackingx_refsource_REDHAT

CVSS V3.1

Score:
3.7
Severity:
LOW
Confidentiality:
Low
Integrity:
None
Availability:
Low
Attack Vector:
Network
Attack Complexity:
High
Privileges Required:
None
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

Red Hat would like to thank Shubham Raj (Causal Security) for reporting this issue.
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