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.
CVE-2026-18664
HIGHPre-NVD 8.28.2—Trending — 3 sources updated this week
EchelonGraph scoreMEDIUM confidence
This high-severity CVE scores 8.2 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.3%, top 76% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).
Triggered by: NVD CVSS baseline
Sources: epss, secondary
8.2EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
- High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 8.2Exploit: None knownExposed: 0
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 8.2
- EG Score
- 8.2(medium)
- EG Risk
- 37(Track)EG Risk 37/100SSVC: Track
EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).
How it’s computedSeverity82% × 45%Exploitation0% × 40%Automatability0% × 15%Action: Routine — remediate on your standard cadence. - EPSS PROB
- 0%
- EPSS %ILE
- 24%
- KEV
- Not listed
Published
August 26, 2026
Last Modified
August 26, 2026
Advisory Details (1)
Auto-updated Aug 26, 2026No patch confirmed yet.
Weakness Classification(2)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 10× in last 7d / 10× in last 30d)
Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.
- 2026-08-30 01:22 UTCEPSS rescore
- 2026-08-29 07:56 UTCEG score recompute
- 2026-08-28 21:41 UTCEPSS rescore
- 2026-08-27 18:07 UTCEG score recompute
- 2026-08-27 14:25 UTCEPSS rescore
- 2026-08-26 15:54 UTCEG score recompute
- 2026-08-26 15:05 UTCEG score recompute
- 2026-08-26 14:46 UTCEPSS rescore
- 2026-08-26 08:49 UTCEG score recompute
- 2026-08-26 08:48 UTCMITRE cvelistV5first tracked
Related CVEs(same CWE)
Same CWE
10 shownCWE-284 · CWE-697
Frequently asked(5)
What is CVE-2026-18664?
CVE-2026-18664 is a high vulnerability published on August 26, 2026. 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…
When was CVE-2026-18664 disclosed?
CVE-2026-18664 was first published in the National Vulnerability Database on August 26, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-18664 actively exploited?
CVE-2026-18664 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 76.2% of all scored CVEs.
What is the CVSS score of CVE-2026-18664?
CVE-2026-18664 has a CVSS v3 base score of 8.2 (NVD).
How do I remediate CVE-2026-18664?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-18664, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.
Dependency Blast Radius
Explore the affected products and dependency analysis for CVE-2026-18664
Is Your Infrastructure Affected by CVE-2026-18664?
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