CVE-2026-12490: When a provide-xfr is given with a tls-auth-name, a secondary requesting a transfer should provide a client ce

Q: How do I fix CVE-2026-12490?

nsd: upgrade to 4.14.3. Exact commands for each OS are on this page.

Q: Is CVE-2026-12490 being exploited?

CVE-2026-12490 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-2026-12490 affect?

CVE-2026-12490 affects nsd. Severity is high (CVSS 7.5). When a provide-xfr is given with a tls-auth-name, a secondary requesting a transfer should provide a client certificate with that name. However, no client certificate is needed when the request comes in over TLS over the regular tls-port (a

Q: How urgent is CVE-2026-12490?

Priority 34/100. High severity; Remotely exploitable, no login, no user action

Routine

HIGH 7.5REMOTEUPGRADE

CVE-2026-12490 is a high-severity flaw (CVSS 7.5) affecting nsd. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

When a provide-xfr is given with a tls-auth-name, a secondary requesting a transfer should provide a client certificate with that name. However, no client certificate is needed when the request comes in over TLS over the regular tls-port (and not the tls-auth-port) or over over TCP over the regular port, when the other conditions of the provide-xfr rule match.

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	0.2% (top 88%)
CISA exploited list	No
Weakness	CWE-284, CWE-306
Published	2026-06-25
Last modified	2026-10-25

Publisher (CNA): NLnet Labs · Vendor: nlnetlabs

Last updated 2026-10-25 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-06-25 07:16 UTCPublished CVE record published
2026-10-25 23:10 UTCUpdated Record last modified

nlnetlabs nsd UPGRADE

Affected: < 4.14.3

Fixed in: 4.14.3

Safe to downgrade to: no unaffected older release

1. Check installed version

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

2. UPGRADE to 4.14.3 (Debian / Ubuntu)

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

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade nsd

Note

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

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-2026-12490?

nsd: upgrade to 4.14.3. Exact commands for each OS are on this page.

Is CVE-2026-12490 being exploited?

CVE-2026-12490 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-2026-12490 affect?

CVE-2026-12490 affects nsd. Severity is high (CVSS 7.5). When a provide-xfr is given with a tls-auth-name, a secondary requesting a transfer should provide a client certificate with that name. However, no client certificate is needed when the request comes in over TLS over the regular tls-port (a

How urgent is CVE-2026-12490?

Priority 34/100. High severity; Remotely exploitable, no login, no user action

Related CVEs

CVE-2026-12244 HIGH 8.8 UPGRADE If NSD is configured as secondary for a zone, the primary of that zone can crash NSD with an AXFR containing a
CVE-2026-12245 HIGH 7.5 UPGRADE NSD from version 4.13.0 has a heap use-after-free bug in logging errors on TLS connections, causing a crash of
CVE-2026-12246 HIGH 8.1 UPGRADE NSD version 4.14.0 introduced a bug where a specially crafted APL RR, with an adflength larger than permitted

References

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