CVE-2023-1386Public exploit

Guest privilege escalation via retained SUID/SGID bits

Published Jul 24, 2023 · Updated Sep 25, 2024

Improper permission preservation in QEMU 9pfs allows local guest OS users to retain SUID or SGID bits on executable writes. The v9fs_file_write_iter() path omits file_modified() processing that normally clears privileged mode bits, while root-run QEMU retains CAP_FSETID and the host filesystem leaves them set. Exploitation requires a root-owned, world-writable SUID or SGID executable on a passthrough 9p share and low-privileged guest access; Red Hat closed the report as not a bug.

CVSS severity7.8
High
EPSS probability0.24%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper permission preservation in QEMU 9pfs allows local guest OS users to retain SUID or SGID bits on executable writes. The v9fs_file_write_iter() path omits file_modified() processing that normally clears privileged mode bits, while root-run QEMU retains CAP_FSETID and the host filesystem leaves them set. Exploitation requires a root-owned, world-writable SUID or SGID executable on a passthrough 9p share and low-privileged guest access; Red Hat closed the report as not a bug.

The record

CVE
CVE-2023-1386
Published
Jul 24, 2023
Updated
Sep 25, 2024
Vendor
Fedora Project
Product
Fedora Linux
Classifications
CWE-281, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jul 24, 2023CVE publishedPublication date reported by the CVE source.
  2. Sep 25, 2024Record 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?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Fedora Project · Fedora LinuxAffected versions are unavailable in this record.
QEMU Project · QEMUAffected versions are unavailable in this record.

Published CVSS scores

3.3Red Hat, Inc.CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
7.8NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-281Improper Preservation of Permissions
T1068Exploitation for Privilege Escalation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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