CVE-2026-18664
criticalpriority · track · 36EPSS 0.004 · 38 %ileDEUSEPSS · scored 2026-10-27
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.
cvss
Technical severity, 0–10. One row per scoring source.
base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–critical · 4.6–9.1
ssvc
A stakeholder decision — act, attend, or track — from exploitation and impact.
weaknesses
The CWE weakness classes this flaw belongs to.
affected products (3)
Products and version ranges known to be affected.
advisories (1)
Vendor and ecosystem advisories describing this.
- WID-SEC-W-2026-3663OpenBSD: Mehrere SchwachstellenDeutsch2026-09-29csaf · cert_bundDE
Ein Angreifer kann mehrere Schwachstellen in OpenBSD ausnutzen, um einen nicht näher spezifizierten Angriff durchzuführen, um Sicherheitsvorkehrungen zu umgehen und um einen Denial of Service Angriff durchzuführen.
sources
Which sources assert this record, and when.
references (1) nvd
External citations — patches, advisories, analysis.
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