CVE-2026-18664 (GCVE-0-2026-18664)
Vulnerability from cvelistv5 – Published: 2026-08-26 08:34 – Updated: 2026-08-26 14:47
VLAI
EPSS
VEX
Title
Wrong interpretation of ACL ranges
Summary
When ranges are used for access control (i.e. of the form 1.2.3.4-1.2.3.25), because NSD wrongly compares the IP address with the range on little endian systems, IPs that were meant to be allowed may be denied, and, IPs that were meant to be denied access could be allowed. An IPv4 address is compared with IPv4 ranges as unsigned 32 bit numbers directly with the endianness of the host, but the values to compare are in network byte order (big-endian). With IPv6 addresses the comparison is done in 4 times a unsigned 32 bit number comparison, again with the endianness of the host where all values are actually in network bye order.
Severity
SSVC
Exploitation: none
Automatable: no
Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-08-26 14:33 UTC
Assigner
NLnet Labs
CNA
References
1 reference
| URL | Tags |
|---|---|
| https://www.nlnetlabs.nl/downloads/nsd/CVE-2026-1… | vendor-advisory |
Impacted products
1 product
| Vendor | Product | Version | CPE status | |
|---|---|---|---|---|
| NLnet Labs | NSD |
Affected:
3.0.0 , < 4.15.1
(semver)
|
guessed |
Date Public
2026-08-26 12:00
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