CVE-2023-2861: Qemu: 9pfs: improper access control on special files

Severity: high (CVSS 7.1 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2023-12-06 · updated 2026-06-17
Weakness: CWE-284

Description

A flaw was found in the 9p passthrough filesystem (9pfs) implementation in QEMU. The 9pfs server did not prohibit opening special files on the host side, potentially allowing a malicious client to escape from the exported 9p tree by creating and opening a device file in the shared folder.

Affected products

QEMU: before 8.1.0 — fixed in 8.1.0

How to fix

Upgrade to a fixed version: QEMU 8.1.0. Check the vendor advisory for mitigations.

References

https://access.redhat.com/security/cve/CVE-2023-2861
https://bugzilla.redhat.com/show_bug.cgi?id=2219266
https://lists.debian.org/debian-lts-announce/2024/03/msg00012.html
https://security.netapp.com/advisory/ntap-20240125-0005/
https://security.netapp.com/advisory/ntap-20240229-0002/
https://access.redhat.com/security/cve/CVE-2023-2861
https://bugzilla.redhat.com/show_bug.cgi?id=2219266
https://lists.debian.org/debian-lts-announce/2024/03/msg00012.html
https://security.netapp.com/advisory/ntap-20240125-0005/
https://security.netapp.com/advisory/ntap-20240229-0002/

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