TI-2026-83880 Aliases CVE-2026-109142 GHSA-p4hg-66rh-w2c8

Authorization bypass in NLnet Labs Krill lets CA impersonate children

LOW 38CWE-639Published 2026-11-02 · Updated 2026-11-02

Key facts

Attack vector: Network
Privileges required: Low
User interaction: None
Attack complexity: High
Impact type: Security bypass
Confidentiality · integrity · availability: High · High · Low
Fix status: Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-639.

Summary

NLnet Labs Krill before 0.16.1 runs provisioning with a parent CA on the same server in-process. Instead of verifying a signed CMS message, it trusts the child identity supplied by the caller, and never checks that this identity belongs to the requesting CA (CWE-639). A remote attacker with low privileges can act as any child of any CA on that server, with high impact to confidentiality and integrity.

Written with Claude Haiku 5.5 from the sources below · 2026-11-02

Description from the CNA

When a CA's parent lives on the same Krill server: instead of building and verifying a signed CMS message, it runs the RFC 6492 provisioning exchange in-process and trusts the child identity (child_handle) that the caller put in the parent contact. Nothing checks that this child identity actually belongs to the CA making the request.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV

EPSS 0.00276 20th percentileScored 2026-11-07

Fix Fixed Krill (NLnet Labs): 0.16.1

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: None
Automatable: No
Technical impact: Total

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	Krill	—	0.16.1	Patch available	CNA

Krill VendorNLnet Labs Affected — Fixed in 0.16.1 Patch available CNA

Remediation

Upgrade NLnet Labs Krill to version 0.16.1, which fixes this flaw.

Written with Claude Haiku 5.5 from the sources below · 2026-11-02

Fix · CNA Krill (NLnet Labs) Fixed in 0.16.1

Timeline

2026-11-02 Threatist record created from CVE-2026-109142
2026-11-02 CISA SSVC decision points changed
2026-11-02 Priority changed: MEDIUM → LOW
2026-11-02 Alias added: GHSA-p4hg-66rh-w2c8

References

Advisory 1

https://www.nlnetlabs.nl/downloads/krill/CVE-2026-109142.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