What’s Vulnerable › Vulnerabilities
CVE-2026-19538: Bypass of BLOCKED ACL items on proxy protocol port over TCP or TLS
- Severity: high (CVSS 7.5 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 0.4% probability of exploitation in the next 30 days
- Public exploit or detection template: none known
- Published: 2026-08-26 · updated 2026-09-08
- Weakness: CWE-290
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 products
- NLnet Labs NSD: from 4.8.0 before 4.15.1 — fixed in 4.15.1
How to fix
Upgrade to a fixed version: NLnet Labs NSD 4.15.1. Check the vendor advisory for mitigations.
References
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