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HIGH · 7.5

CVE-2026-19538

The BLOCKED access control list items that are evaluated to deny access on the the proxy protocol port can be bypassed completely when connecting over TCP or TLS and sending the query twice on connect...

Vulnerability Description

The BLOCKED access control list items that are evaluated to deny access on the the proxy protocol port can be bypassed completely when connecting over TCP or TLS and sending the query twice on connection that is kept open.

CVSS Score

7.5

HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
HIGH
Availability
NONE

Affected Products

VendorProductVersions
NlnetlabsNsd>= 4.8.0, < 4.15.1

Related Weaknesses (CWE)

CWE-290CWE-672

References

FAQ

What is CVE-2026-19538?

CVE-2026-19538 is a vulnerability with a CVSS score of 7.5 (HIGH). The BLOCKED access control list items that are evaluated to deny access on the the proxy protocol port can be bypassed completely when connecting over TCP or TLS and sending the query twice on connect...

How severe is CVE-2026-19538?

CVE-2026-19538 has been rated HIGH with a CVSS base score of 7.5/10. Review the CVSS metrics above for detailed severity breakdown.

Is there a patch for CVE-2026-19538?

Check the references section above for vendor advisories and patch information. Affected products include: Nlnetlabs Nsd.