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Fencer Vulns
high 7.5

CVE-2026-12490 json

Bypass of client certificate verification with transfer over TLS

published 2026-06-25 4 mo ago modified 2026-10-25 14 d ago also EUVD-2026-39185

cvss
7.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 12%
public exploits
0
none known

Summary

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.

Patch / fix

  • NLnet Labs NSD 4.14.3
  • nsd Debian 14 4.14.3-1

debian advisories DEBIAN-CVE-2026-12490

  • nsd Ubuntu Pro 26.04 LTS 4.14.0-1ubuntu0.1~esm1

ubuntu advisories UBUNTU-CVE-2026-12490

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • nsd openSUSE Leap 16.0 4.14.3-bp160.1.1
  • nsd openSUSE Tumbleweed 4.14.3-1.1

opensuse advisories openSUSE-SU-2026:21502-1openSUSE-SU-2026:11395-1

  • nsd Alpine 3.24 4.14.3-r0

alpine advisories ALPINE-CVE-2026-12490

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-12490 updated cvss 7.5

nsd: Bypass of client certificate verification with transfer over TLS

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
4 mo ago

Exploit prediction

0.22% chance of exploitation in the next 30 days, higher than 12% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 4.0 8.2 CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N
CNA 4.0 8.2 CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Affected products

  • NLnet Labs NSD

Classification

Weakness
  • CWE-306 Missing Authentication for Critical Functionality
  • CWE-284 Improper Access Control

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.