Description
A flaw exists in the nbdkit "blocksize" filter that can be triggered by a specific type of client request. When a client requests block status information for a very large data range, exceeding a certain limit, it causes an internal error in the nbdkit, leading to a denial of service.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| — | nbdkit | 1.21.16 – < 1.38.6, 1.40.0 – < 1.40.6, 1.42.0 – < 1.42.3 | 1.38.6 |
| Red Hat | Red Hat Enterprise Linux 10 | — | — |
| Red Hat | Red Hat Enterprise Linux 7 | — | — |
| Red Hat | Red Hat Enterprise Linux 8 | — | — |
| Red Hat | Red Hat Enterprise Linux 8 Advanced Virtualization | — | — |
| Red Hat | Red Hat Enterprise Linux 9 | — | — |
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 | nbdkit | 1.42.3-1 | — |
| Debian 13 | nbdkit | 1.42.3-1 | — |
| Debian 12 | nbdkit | No fix yet | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | nbdkit | No fix yet | — |
| Ubuntu 26.04 LTS | nbdkit | No fix yet | — |
| Ubuntu 25.10 | nbdkit | No fix yet | — |
| Ubuntu 24.04 LTS | nbdkit | No fix yet | — |
| Ubuntu 22.04 LTS | nbdkit | No fix yet | — |
Show 2 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 20.04 LTS | nbdkit | No fix yet | — |
| Ubuntu 16.04 LTS | nbdkit | No fix yet | — |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP7 | nbdkit | 1.40.6-150700.4.3.1 | SUSE-SU-2025:01888-1 |
| SLES 15 SP6 | nbdkit | 1.36.5-150400.3.9.1 | SUSE-SU-2025:01889-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | nbdkit | 1.42.3-1.1 | openSUSE-SU-2025:15088-1 |
| openSUSE Leap 15.6 | nbdkit | 1.36.5-150400.3.9.1 | SUSE-SU-2025:01889-1 |
Azure Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Azure Linux 3 | nbdkit | 1.35.3-7 | — |
| Azure Linux 2 (CBL-Mariner) | nbdkit | 1.35.3-4 | — |
Advisories 3
- openSUSE-SU-2025:15088-1 nbdkit-1.42.3-1.1 on GA media SUSE / openSUSE Security Updates · Mar 23, 2026
- SUSE-SU-2025:01889-1 Security update for nbdkit SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2025:01888-1 Security update for nbdkit SUSE / openSUSE Security Updates · Jun 11, 2025