A flaw was found in the virtio-fs shared file system daemon (virtiofsd) of QEMU.
Priority LOW 16CWE-281Published · Updated
Key facts
- Attack vector
- Local
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- None · Low · None
- Fix status
- No fix listed
Attack profile from CVSS 3.1 · NVD. Fix status from CNA and Red Hat.
Summary
A flaw was found in the virtio-fs shared file system daemon (virtiofsd) of QEMU. The new 'xattrmap' option may cause the 'security.capability' xattr in the guest to not drop on file write, potentially leading to a modified, privileged executable in the guest. In rare circumstances, this flaw could be used by a malicious user to elevate their privileges within the guest.
Why it matters now
EPSS 0.00377 31st percentileScored 2026-11-07
Fix No fix listed No fixed version in the sources yet
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| — | QEMU | qemu 5.2.50 | — | No fix listed | CNA |
- QEMU Vendor— Affected qemu 5.2.50 Fixed in — No fix listed CNA
Remediation
No fixed version listed by the sources yet.
Vendor assessments
Red Hat
Red Hat rating: Low. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 9 | Affected | No fix yet |
Not affected: 6 products
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 8
- Red Hat Enterprise Linux 8 Advanced Virtualization
- Red Hat OpenStack Platform 10 (Newton)
- Red Hat OpenStack Platform 13 (Queens)
Timeline
- 2026-10-02 Threatist record created from CVE-2021-20263
- 2026-10-03 Alias added: GHSA-349h-phx6-ghfj
References
More Qemu vulnerabilities
- TI-2024-16148 QEMU before 8.2.0 has an integer underflow, and resultant buffer overflow, via a TI… CVSS 3.1HIGH 8.8
- TI-2022-02736 Uncontrolled resource consumption in QEMU CVSS 3.1HIGH 7.8
- TI-2023-02681 Qemu: 9pfs: improper access control on special files CVSS 3.1HIGH 7.1
- TI-2019-09678 The QMP migrate command in QEMU version 4.0.0 and earlier is vulnerable to OS command… CVSS 3.0CRITICAL 9.8
- TI-2024-03326 Qemu-kvm: net: assertion failure in update_sctp_checksum() CVSS 3.1MEDIUM 5.5
- TI-2023-22631 QEMU through 8.0.0 could trigger a division by zero in scsi_disk_reset in… CVSS 3.1MEDIUM 5.5
Sources
- CVE-2021-20263 · CVE Program
- CVE-2021-20263 · NVD
- FIRST EPSS
- GHSA-349h-phx6-ghfj · GitHub Advisory Database · CC BY 4.0
- CVE-2021-20263 · Red Hat security data · CC BY 4.0
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