CVE-2026-3888: Important Snap Flaw Enables Local Privilege Escalation to Root | Qualys
Summary: Qualys' Threat Research Unit identified CVE-2026-3888, a local privilege escalation flaw in default installations of Ubuntu Desktop 24.04 and later, where an unprivileged local attacker can reach full root through the interaction of snap-confine and systemd-tmpfiles. The flaw is rated High with a CVSS v3.1 score of 7.8, and exploitation depends on a time-based window of 10 to 30 days tied to systemd-tmpfiles' scheduled cleanup of /tmp.
What you should know: The exploit needs no user interaction and only low privileges, but it turns a default Ubuntu Desktop install into full root compromise once the cleanup timing lines up - and the fix is a snapd upgrade to 2.73+ubuntu24.04.2 or later, so any host still on an earlier build is exposed.
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- Topics
- Vulnerabilities & Patching
- Mentions
- CVE-2026-3888
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