{"answers":{"affected":"It affects 1 product.","exploited":"There is no known exploitation of CVE-2026-18664 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2026-18664 is a high-severity authentication bypass vulnerability in NLnet Labs NSD, published on 26 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2026-18664 and fix it if it is affected.\n\nWhat it is: CVE-2026-18664 is a high-severity authentication bypass vulnerability in NLnet Labs NSD, published on 26 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.\nExploitation: There is no known exploitation of CVE-2026-18664 in the wild and no public exploit code.\n\nAffected product: NLnet Labs NSD. No package-level version data is available, so check the vendor advisory linked from the reference page.\n\nTask:\n1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.\n2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.\n3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.\n4. Run the tests and summarise what changed and why.\n5. If nothing in the project is affected, say so and change nothing.\n\nReference: https://insights.sbomify.com/CVE-2026-18664/ (Markdown: https://insights.sbomify.com/CVE-2026-18664/index.md)","id":"CVE-2026-18664","markdown":"https://insights.sbomify.com/CVE-2026-18664/index.md","name":"CVE-2026-18664","record":{"aliases":["DEBIAN-CVE-2026-18664","GHSA-fw9f-54cp-j7fc","UBUNTU-CVE-2026-18664"],"analysis":{"component_type":"server_software","fix_type":"patch","impacts":["security_bypass"],"network_reachable":"yes","non_default_config":true,"product_category":"NSD DNS server","requires_auth":"none","summary":"Attackers can bypass IP-based access controls on NSD DNS servers due to endianness errors in range comparisons, allowing unauthorized access or blocking legitimate users.","user_interaction":"not_required","vuln_class":"auth_bypass"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"NLnet Labs","cpe":[{"product":"nsd","vendor":"nlnetlabs"}],"cvss":{"score":8.2,"severity":"high","source":"cna","vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N","version":"4.0"},"cwes":[{"id":"CWE-697","name":"Incorrect Comparison"},{"id":"CWE-284","name":"Improper Access Control"}],"description":"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.","ecosystems":[],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"none_known"},"has_fix":true,"headline":"Wrong interpretation of ACL ranges","id":"CVE-2026-18664","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":null,"products":[],"type":"auth_bypass","year":"2026"},"n_packages":0,"n_references":1,"next":{"headline":"Library Management System \u003c 3.6.7 - Subscriber+ SQL Injection via Filter Value","id":"CVE-2026-18666"},"packages":[],"prev":{"headline":"Use after free in Red Hat Directory Server 11","id":"CVE-2026-18663"},"products":["NSD"],"published":"2026-08-26","related":[{"cvss_score":8.7,"headline":"Heap overflow and crash with crafted SVCB RR","id":"CVE-2026-12244","kev_date_added":null,"published":"2026-06-25"},{"cvss_score":8.7,"headline":"Denial of DNS over TLS service by any DoT client","id":"CVE-2026-12245","kev_date_added":null,"published":"2026-06-25"},{"cvss_score":8.2,"headline":"Remote UDP DoS by sending multiple DNS Cookie options","id":"CVE-2026-19401","kev_date_added":null,"published":"2026-08-26"},{"cvss_score":8.2,"headline":"Bypass of BLOCKED ACL items on proxy protocol port over TCP or TLS","id":"CVE-2026-19538","kev_date_added":null,"published":"2026-08-26"},{"cvss_score":8.2,"headline":"Bypass of client certificate verification with transfer over TLS","id":"CVE-2026-12490","kev_date_added":null,"published":"2026-06-25"},{"cvss_score":7.5,"headline":"Denial of service in n/a","id":"CVE-2016-6173","kev_date_added":null,"published":"2017-02-09"}],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"},{"class":"attribution","licence":"US public information, NVD API terms","name":"NVD"},{"class":"attribution","licence":"CWE Terms of Use","name":"CWE (MITRE)"},{"class":"attribution","licence":"FIRST CVSS licence","name":"CVSS (FIRST)"}],"ssvc":{"automatable":"no","exploitation":"none","technical_impact":"partial"},"state":"PUBLISHED","updated":"2026-08-26","vendors":["NLnet Labs"]},"summary":"Attackers can bypass IP-based access controls on NSD DNS servers due to endianness errors in range comparisons, allowing unauthorized access or blocking legitimate users.","url":"https://insights.sbomify.com/CVE-2026-18664/"}