CVE-2026-10846: NLnet Labs ldns 1.2.0 up to and including versions 1.9.0, when used in applications as (stub) resolver over UD

Routine

HIGH 7.5REMOTEUPGRADE

CVE-2026-10846 is a high-severity flaw (CVSS 7.5) affecting ldns. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

NLnet Labs ldns 1.2.0 up to and including versions 1.9.0, when used in applications as (stub) resolver over UDP, lacks matching the query destination address and port with the response source address and port. Furthermore not the query ID, neither the question of the query is matched with that of the response. This makes applications, that use ldns for (stub) resolver functionality over UDP, vulnerable for off-path poisoning attacks. The drill to

Why this priority

High severity
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.1% (top 96%)
CISA exploited list	No
Weakness	CWE-346
Published	2026-06-10
Last modified	2026-07-23

Publisher (CNA): NLnet Labs · Vendor: nlnetlabs

Last updated 2026-07-23 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-06-10 07:16 UTCPublished CVE record published
2026-07-23 09:10 UTCUpdated Record last modified

nlnetlabs ldns UPGRADE

Affected: >= 1.2.0 and < 1.9.1

Fixed in: 1.9.1

Safe to downgrade to: a release before 1.2.0

1. Check installed version

apt-cache policy ldns || rpm -q ldns || ldns --version

2. UPGRADE to 1.9.1 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade ldns

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade ldns

Note

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

3. If no update is available yet, DOWNGRADE to a release before 1.2.0 (Debian / Ubuntu)

apt-cache madison ldns sudo apt install ldns=<VERSION_BEFORE_1.2.0> sudo apt-mark hold ldns

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list ldns sudo dnf downgrade ldns-<VERSION_BEFORE_1.2.0> sudo dnf versionlock add ldns

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Advisories and coverage

Official advisories

AlmaLinux Errata: [ALSA-2026:50108] Important: ldns security update 2026-08-06

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-2026-10846?

ldns: upgrade to 1.9.1. Exact commands for each OS are on this page.

Is CVE-2026-10846 being exploited?

CVE-2026-10846 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-2026-10846 affect?

CVE-2026-10846 affects ldns. Severity is high (CVSS 7.5). NLnet Labs ldns 1.2.0 up to and including versions 1.9.0, when used in applications as (stub) resolver over UDP, lacks matching the query destination address and port with the response source address and port. Furthermore not the query ID,

How urgent is CVE-2026-10846?

Priority 32/100. High severity; Remotely exploitable, no login, no user action

References

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