CVE-2022-26495: In nbd-server in nbd before 3.24, there is an integer overflow with a resultant heap-based buffer overflow

Q: How do I fix CVE-2022-26495?

network block device: upgrade to 3.24; debian linux: mitigate or apply the listed mitigation; fedora: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Q: Is CVE-2022-26495 being exploited?

CVE-2022-26495 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2022-26495 affect?

CVE-2022-26495 affects network block device, debian linux, fedora. Severity is critical (CVSS 9.8). In nbd-server in nbd before 3.24, there is an integer overflow with a resultant heap-based buffer overflow. A value of 0xffffffff in the name length field will cause a zero-sized buffer to be allocated for the name, resulting in a write to

Q: How urgent is CVE-2022-26495?

Priority 71/100. Critical severity; Public exploit reference; Remotely exploitable, no login, no user action; On your watchlist

This week

CRITICAL 9.8REMOTEWATCHLISTUPGRADEMITIGATEMITIGATE

CVE-2022-26495 is a critical-severity flaw (CVSS 9.8) affecting network block device, debian linux, fedora. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

In nbd-server in nbd before 3.24, there is an integer overflow with a resultant heap-based buffer overflow. A value of 0xffffffff in the name length field will cause a zero-sized buffer to be allocated for the name, resulting in a write to a dangling pointer. This issue exists for the NBD_OPT_INFO, NBD_OPT_GO, and NBD_OPT_EXPORT_NAME messages.

Why this priority

Critical severity
Public exploit reference
Remotely exploitable, no login, no user action
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	2.9% (top 13%)
CISA exploited list	No
Weakness	CWE-190
Published	2022-03-06
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: debian · fedoraproject · network block device project

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2022-03-06 06:15 UTCPublished CVE record published
2026-06-17 04:35 UTCUpdated Record last modified

network block device project network block device UPGRADE

Affected: < 3.24

Fixed in: 3.24

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy network-block-device || rpm -q network-block-device || network-block-device --version

2. UPGRADE to 3.24 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade network-block-device

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade network-block-device

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

debian debian linux MITIGATE

Affected: 9.0 · 10.0 · 11.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 9.0

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

fedoraproject fedora MITIGATE

Affected: 34 · 35 · 36

Fixed in: no fixed release known

Safe to downgrade to: a release before 34

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

Exact fixes by distribution

A distro patch exists: prefer upgrading over downgrading.

Fedora 46 · nemo · FIXED · 6.8.0-1.fc46 · FEDORA-2026-0edead723f · source

sudo dnf upgrade --advisory=FEDORA-2026-0edead723f

Fedora ELN · composer · FIXED · 2.11.1-1.eln159 · FEDORA-2026-cb4f992456 · source

sudo dnf upgrade --advisory=FEDORA-2026-cb4f992456

Ubuntu 20.04 · nbd · FIXED · 1:3.20-1ubuntu0.1

sudo apt update && sudo apt install --only-upgrade nbd dpkg --compare-versions "$(dpkg-query -W -f='${Version}' nbd)" ge "1:3.20-1ubuntu0.1" && echo PATCHED || echo STILL-VULNERABLE

Ubuntu 22.04 · nbd · FIXED · 1:3.23-3ubuntu1

sudo apt update && sudo apt install --only-upgrade nbd dpkg --compare-versions "$(dpkg-query -W -f='${Version}' nbd)" ge "1:3.23-3ubuntu1" && echo PATCHED || echo STILL-VULNERABLE

Ubuntu 24.04 · nbd · FIXED · 1:3.23-3ubuntu1

sudo apt update && sudo apt install --only-upgrade nbd dpkg --compare-versions "$(dpkg-query -W -f='${Version}' nbd)" ge "1:3.23-3ubuntu1" && echo PATCHED || echo STILL-VULNERABLE

Ubuntu 24.10 · nbd · FIXED · 1:3.23-3ubuntu1

sudo apt update && sudo apt install --only-upgrade nbd dpkg --compare-versions "$(dpkg-query -W -f='${Version}' nbd)" ge "1:3.23-3ubuntu1" && echo PATCHED || echo STILL-VULNERABLE

Ubuntu 25.04 · nbd · FIXED · 1:3.23-3ubuntu1

sudo apt update && sudo apt install --only-upgrade nbd dpkg --compare-versions "$(dpkg-query -W -f='${Version}' nbd)" ge "1:3.23-3ubuntu1" && echo PATCHED || echo STILL-VULNERABLE

Debian 12 · nbd · FIXED · 1:3.24-1

sudo apt update && sudo apt install --only-upgrade nbd dpkg --compare-versions "$(dpkg-query -W -f='${Version}' nbd)" ge "1:3.24-1" && echo PATCHED || echo STILL-VULNERABLE

Debian 13 · nbd · FIXED · 1:3.24-1

sudo apt update && sudo apt install --only-upgrade nbd dpkg --compare-versions "$(dpkg-query -W -f='${Version}' nbd)" ge "1:3.24-1" && echo PATCHED || echo STILL-VULNERABLE

Alpine 3.20 · nbd · FIXED · nbd-3.24-r0

apk add --upgrade nbd apk info -v nbd

Alpine 3.21 · nbd · FIXED · nbd-3.24-r0

apk add --upgrade nbd apk info -v nbd

Alpine 3.22 · nbd · FIXED · nbd-3.24-r0

apk add --upgrade nbd apk info -v nbd

Alpine 3.23 · nbd · FIXED · nbd-3.24-r0

apk add --upgrade nbd apk info -v nbd

Public exploits and detection

Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.

Write-up: lists.debian.org/nbd/2022/01/msg00037.html

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2022-26495?

network block device: upgrade to 3.24; debian linux: mitigate or apply the listed mitigation; fedora: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2022-26495 being exploited?

CVE-2022-26495 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2022-26495 affect?

CVE-2022-26495 affects network block device, debian linux, fedora. Severity is critical (CVSS 9.8). In nbd-server in nbd before 3.24, there is an integer overflow with a resultant heap-based buffer overflow. A value of 0xffffffff in the name length field will cause a zero-sized buffer to be allocated for the name, resulting in a write to

How urgent is CVE-2022-26495?

Priority 71/100. Critical severity; Public exploit reference; Remotely exploitable, no login, no user action; On your watchlist

Software pages

Debian vulnerabilities

Related CVEs

CVE-2022-26496 CRITICAL 9.8 UPGRADE MITIGATE In nbd-server in nbd before 3.24, there is a stack-based buffer overflow

References

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