Description
An assertion failure issue was found in the Network Block Device(NBD) Server in all QEMU versions before QEMU 5.0.1. This flaw occurs when an nbd-client sends a spec-compliant request that is near the boundary of maximum permitted request length. A remote nbd-client could use this flaw to crash the qemu-nbd server resulting in a denial of service.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Red Hat | QEMU: | all QEMU versions before QEMU 5.0.1 | — |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | qemu | 1:5.0-6 | — |
| Debian 13 | qemu | 1:5.0-6 | — |
| Debian 12 | qemu | 1:5.0-6 | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 20.04 LTS | qemu | 1:4.2-3ubuntu6.4 | USN-4467-1 |
| Ubuntu 18.04 LTS | qemu | 1:2.11+dfsg-1ubuntu7.31 | USN-4467-1 |
| Ubuntu 16.04 LTS | qemu | 1:2.5+dfsg-5ubuntu10.45 | USN-4467-1 |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 8 | SLOF | 20191022-3.git899d9883.module+el8.2.0+5449+efc036dd | RHBA-2020:3172 |
| RHEL 8 | hivex +6 | 1.3.18-20.module+el8.2.0+5588+63a201c3 | RHBA-2020:3172 |
| RHEL 8 | libguestfs-winsupport | 8.2-1.module+el8.2.0+5590+82cd80df | RHBA-2020:3172 |
| RHEL 8 | libiscsi +2 | 1.18.0-8.module+el8.2.0+4793+b09dd2fb | RHBA-2020:3172 |
| RHEL 8 | libnbd +5 | 1.2.2-1.module+el8.2.0+5644+32ac38d4 | RHBA-2020:3172 |
| RHEL 8 | libtpms +1 | 0.7.0-1.20191018gitdc116933b7.module+el8.2.0+4793+b09dd2fb | RHBA-2020:3172 |
| RHEL 8 | libvirt +28 | 6.0.0-25.module+el8.2.1+7154+47ffd890 | RHBA-2020:3172 |
| RHEL 8 | libvirt-dbus | 1.3.0-2.module+el8.2.0+4793+b09dd2fb | RHBA-2020:3172 |
| RHEL 8 | libvirt-python +1 | 6.0.0-1.module+el8.2.0+5453+31b2b136 | RHBA-2020:3172 |
| RHEL 8 | nbdkit +13 | 1.16.2-4.module+el8.2.1+6710+effcb1df | RHBA-2020:3172 |
| RHEL 8 | netcf +2 | 0.2.8-12.module+el8.2.0+4793+b09dd2fb | RHBA-2020:3172 |
| RHEL 8 | perl-Sys-Virt | 6.0.0-1.module+el8.2.0+5488+267def79 | RHBA-2020:3172 |
| RHEL 8 | python-pyvmomi +1 | 6.7.1-7.module+el8.2.0+4793+b09dd2fb | RHBA-2020:3172 |
| RHEL 8 | qemu-img +10 | 15:4.2.0-29.module+el8.2.1+7297+a825794d | RHBA-2020:3172 |
| RHEL 8 | seabios +2 | 1.13.0-2.module+el8.2.1+7284+aa32a2c4 | RHBA-2020:3172 |
| RHEL 8 | sgabios +1 | 1:0.20170427git-3.module+el8.2.0+4793+b09dd2fb | RHBA-2020:3172 |
| RHEL 8 | supermin +1 | 5.1.19-10.module+el8.2.0+4793+b09dd2fb | RHBA-2020:3172 |
| RHEL 8 | swtpm +3 | 0.2.0-2.20200127gitff5a83b.module+el8.2.0+5579+d71178e0 | RHBA-2020:3172 |
| RHEL 8 | virglrenderer +2 | 0.8.2-1.module+el8.2.0+5777+d9c2af8c | RHBA-2020:3172 |
| RHEL 8 | virt-dib +25 | 1:1.40.2-24.module+el8.2.1+7154+47ffd890 | RHBA-2020:3172 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP2 | qemu | 4.2.1-11.4.4 | SUSE-SU-2020:2015-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | qemu | 6.1.0-32.1 | openSUSE-SU-2024:11287-1 |
| openSUSE Leap 15.2 | qemu +2 | 4.2.1-lp152.9.3.1 | openSUSE-SU-2020:1108-1 |
Advisories 6
- RHBA-2020:3172 Red Hat Bug Fix Advisory: Advanced Virtualization bug fix and enhancement update Red Hat Security Advisories (RHSA) · Aug 6, 2026
- USN-4467-1 qemu vulnerabilities Ubuntu Security Notices (USN) · Apr 27, 2026
- openSUSE-SU-2020:1108-1 Security update for qemu SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2020:2015-1 Security update for qemu SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2024:11287-1 qemu-6.1.0-32.1 on GA media SUSE / openSUSE Security Updates · May 7, 2025
- WID-SEC-2024-1974 QEMU: Schwachstelle ermöglicht Denial of Service BSI CERT-Bund (WID) · Sep 2, 2024