Privilege escalation or crash via stale pixmap references
Published Oct 25, 2023 · Updated Jul 11, 2026
Use-after-free in Xvfb on Red Hat Enterprise Linux 7 through 9 allows local users to escalate privileges or crash the X server. The framebuffer screen-cleanup path bypasses the next stackable module and retains references to a freed screen pixmap, which a lower-layer cleanup later dereferences. Exploitation requires legacy Zaphod mode, multiple protocol screens, and pointer warping from screen 1 to screen 0 during reset or shutdown; Xvfb normally runs without root privileges.
Summary
What happened
Use-after-free in Xvfb on Red Hat Enterprise Linux 7 through 9 allows local users to escalate privileges or crash the X server. The framebuffer screen-cleanup path bypasses the next stackable module and retains references to a freed screen pixmap, which a lower-layer cleanup later dereferences. Exploitation requires legacy Zaphod mode, multiple protocol screens, and pointer warping from screen 1 to screen 0 during reset or shutdown; Xvfb normally runs without root privileges.
The record
- CVE
- CVE-2023-5574
- Published
- Oct 25, 2023
- Updated
- Jul 11, 2026
- Vendor
- Red Hat
- Product
- Red Hat Enterprise Linux 8
- Classifications
- CWE-416, T1068
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Oct 25, 2023CVE publishedPublication date reported by the CVE source.
- Jul 11, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Affected versions are unavailable in this record. Check the vendor advisory for version and patch details.
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
What attackers are doing with it
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Public exploit references
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Technologies
Your stack
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Your stack
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