vulntracker.iovulntracker.io
© 2026 vulntracker.io

CVE-2026-19538

Bypass of BLOCKED ACL items on proxy protocol port over TCP or TLS

HIGH
7.5
CVSS Score
Published: August 26, 2026 at 08:47 AM UTC
Updated: September 8, 2026 at 07:59 PM UTC
1 product affected across 1 vendorNsd

Using NSD by NLnet Labs?

Get instant alerts when new vulnerabilities affect NSD - before attackers find them.

Real-time alertsTrack your software stackFree plan available
Start FreeSign In
Severity
HIGH7.5
Exploit prediction
EPSS 0.4%
SSVC
No known exploit

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Nsd· Nlnetlabs
95%
4.8.0 ≤ v < 4.15.14.8.0
Affected range stops below 4.15.1, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

Patch and advisory references

References (1)

Vendor Advisory
Source: cverecord
https://www.nlnetlabs.nl/downloads/nsd/CVE-2026-19538.txt

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

7.5HIGH[email protected]
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
HIGH
Availability
NONE
Vector?

Quick Info

StatusANALYZED
CWE
CWE-290CWE-672

Get alerted

Stop reading CVE feeds looking for your own stack

Track the products you run and VulnTracker tells you when a new CVE affects them — with what is known about fixing it, and nothing about the rest.

Create accountSign in
Free plan, no card