TI-2026-12295 Aliases CVE-2026-14586 GHSA-x2gg-pjp4-c6g3

Assertion in libngtcp2 when under pressure in high concurrency DNS-over-QUIC environments

LOW 27CWE-617Published 2026-07-22 · Updated 2026-07-22

Key facts

Attack vector: Network
Privileges required: None
User interaction: None
Attack complexity: High
Impact type: Denial of service
Confidentiality · integrity · availability: None · None · High
Fix status: Partial Red Hat: 1 fixed, 4 without a fix

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat. Impact type from CWE-617.

Summary

In NLnet Labs Unbound 1.22.0 up to and including 1.25.1, in DNS-over-QUIC environments, with high concurrency and under pressure, an assertion in libngtcp2 about monotonic timestamps could trigger and result in server termination and thus denial of service. When interfacing with libngtcp2, for DNS-over-QUIC support in Unbound, it is expected to use monotonic time. Unbound was using realtime instead, and in DoQ environments with high concurrency and under pressure, an assert in libngtcp2 for the quic timestamp would trigger and terminate the server.This vulnerability needs Unbound to be compiled with DoQ support ('--with-libngtcp2') and the 'quic-port' to be configured for the listening interfaces.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV

EPSS 0.00367 30th percentileScored 2026-11-07

Fix Partial Unbound (NLnet Labs): 1.25.2Red Hat: 1 advisoryRed Hat: 1 fixed, 4 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: None
Automatable: No
Technical impact: Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
NLnet Labs	Unbound	1.22.0 to before 1.25.2	1.25.2	Patch available	CNA

Unbound VendorNLnet Labs Affected 1.22.0 to before 1.25.2 Fixed in 1.25.2 Patch available CNA

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPE	Versions	Role	Vendor
cpe:2.3:a:nlnetlabs:unbound::::::::	—	—	NLNETLABS

cpe:2.3:a:nlnetlabs:unbound:*:*:*:*:*:*:*:* Versions — — ·NLNETLABS

Remediation

Fix · CNA Unbound (NLnet Labs) Fixed in 1.25.2

Red Hat 1 advisory

RHSA-2026:43588 Released 2026-07-22 · Red Hat rating Important
Red Hat Hardened Images RPMs bug fix and enhancement update
- Red Hat Hardened Images python3-unbound-1.25.2-0.1.hum1@aarch64, python3-unbound-1.25.2-0.1.hum1@x86_64, unbound-1.25.2-0.1.hum1@aarch64 +14

Fixed in the same release

Records fixed by the same vendor advisory or release, as the CNA lists them.

Release · 2026-07-22
NLnet Labs Unbound 1.25.2
24 records Highest priority Priority LOW 24 LOW
Other records, highest priority first
- TI-2026-40374 'dns-error-reporting: yes' leads to stack buffer overflowPriority LOW 39
- TI-2026-29375 Packet of death for DNSCrypt over TCPPriority LOW 39
- TI-2026-25166 Remote DNS-over-QUIC denial of service due to `quic-size` budget bypassPriority LOW 39
Show all 24 records →

Vendor assessments

Red Hat

Red Hat rating: Moderate. Red Hat's page for this CVE →

Product	Status	Plan or fix
Red Hat Enterprise Linux 10	Affected	No fix yet: Fix deferred
Red Hat Enterprise Linux 9	Affected	No fix yet: Fix deferred
Red Hat OpenShift Container Platform 4	Affected	No fix yet: Fix deferred
Red Hat OpenShift Container Platform 5	Affected	No fix yet: Fix deferred
Red Hat Hardened Images	Fixed	RHSA-2026:43588

Not affected: 3 products

Red Hat Enterprise Linux 6
Red Hat Enterprise Linux 7
Red Hat Enterprise Linux 8

Timeline

2026-10-02 Threatist record created from CVE-2026-14586
2026-10-03 Alias added: GHSA-x2gg-pjp4-c6g3
2026-11-05 Affected versions changed · Red Hat

References

Advisory 1

https://www.nlnetlabs.nl/downloads/unbound/CVE-2026-14586.txt

TI-2026-25690 Possible arbitrary code execution during DNSSEC validation CVSS 4.0CRITICAL 9.1
TI-2026-56302 Heap buffer overflow and possible Remote Code Execution when digesting DNSKEY CVSS 4.0CRITICAL 9.1
TI-2026-31146 Crash during DNSSEC validation of malicious content CVSS 4.0HIGH 8.7
TI-2026-31135 Heap overflow with multiple NSID, COOKIE, PADDING EDNS options CVSS 4.0HIGH 8.7
TI-2026-36436 Routinator crashes on specifically crafted RRDP XML files CVSS 4.0HIGH 8.7
TI-2026-36433 Routinator exits when accepting an incoming HTTP or RTR connection fails CVSS 4.0HIGH 8.7

See all 96 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences