{"id":"CVE-2026-35501","aliases":[],"cve":{"records":[{"id":"CVE-2026-35501","source":"NLnet Labs","state":"PUBLISHED","reasons":[],"replacements":[],"disputed":false,"unsupportedWhenAssigned":false,"reserved":"2026-06-22T10:11:10.543Z","published":"2026-10-21T08:56:55.811Z","modified":"2026-10-29T19:05:26.623Z"}],"publishers":[{"name":"NLnet Labs","role":"CNA","organizationId":"206fc3a0-e175-490b-9eaa-a5738056c9f6","modified":"2026-10-21T08:56:55.811Z"},{"name":"CISA-ADP","role":"ADP","organizationId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","modified":"2026-10-29T19:05:26.623Z"}],"references":[{"url":"https://www.nlnetlabs.nl/downloads/unbound/CVE-2026-35501.txt","tags":["vendor-advisory"],"source":"NLnet Labs"}],"weaknesses":[{"id":"CWE-354","description":"CWE-354: Improper Validation of Integrity Check Value","source":"NLnet Labs"}],"applicability":[],"prioritization":[{"source":"CISA-ADP","type":"SSVC","role":"CISA Coordinator","timestamp":"2026-10-29T19:05:15.135425Z","decisions":[{"name":"Exploitation","value":"none"},{"name":"Automatable","value":"no"},{"name":"Technical Impact","value":"partial"}]}]},"title":"Bypass of a configured island trust anchor underneath an insecure parent from an atacker-controlled NSEC record.","titleSource":"NLnet Labs","descriptionSource":"NLnet Labs","description":"When NLnet Labs Unbound 1.0.1 up to and including version 1.26.1 is configured with both a root trust anchor and an additional 'trust-anchor:' for an island-of-security zone whose parent is provably insecure under the root chain, a malicious actor with a forged NSEC reply with the SOA bit cleared can trick Unbound to treat the configured trust island as insecure. This happens because the DNSSEC validator in Unbound accepts and caches the NSEC insecure response bypassing the RRSIG validation that the validator was supposed to do. The acceptance of the NSEC record at the trust anchor apex was allowed due to and old fix for type DS and NSEC queries from clients when trust anchor for that name existed.","score":3.7,"severity":"low","published":"2026-10-21T08:56:55.811Z","modified":"2026-10-29T19:05:26.623Z","withdrawn":false,"knownExploited":false,"affected":[],"products":[{"vendor":"NLnet Labs","name":"Unbound","platforms":[],"versions":[{"version":"1.0.1","status":"affected","lessThan":"1.26.2","versionType":"semver"}],"defaultStatus":"unaffected","cpes":[],"source":"NLnet Labs","url":"https://www.cve.org/CVERecord?id=CVE-2026-35501"}],"remediation":[{"text":"This issue is fixed starting with version 1.26.2","source":"NLnet Labs","url":"https://www.cve.org/CVERecord?id=CVE-2026-35501"}],"references":["https://www.nlnetlabs.nl/downloads/unbound/CVE-2026-35501.txt"],"sources":[{"name":"CVE","id":"CVE-2026-35501","modified":"2026-10-29T19:05:26.623Z","url":"https://www.cve.org/CVERecord?id=CVE-2026-35501"}],"assessments":[{"source":"NLnet Labs","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N","score":3.7}],"sourceAffected":[],"observedAt":"2026-10-29T19:29:44.502Z","kev":{"status":"not-listed","checkedAt":"2026-10-31T13:55:32.867Z"},"coverage":[{"source":"NVD","status":"available","checkedAt":"2026-10-29T19:35:34.812Z","attemptedAt":"2026-10-29T19:35:34.812Z"},{"source":"GHSA","status":"available","checkedAt":"2026-10-29T19:35:34.806Z","attemptedAt":"2026-10-29T19:35:34.806Z"},{"source":"EUVD","status":"available","checkedAt":"2026-10-29T19:35:33.120Z","attemptedAt":"2026-10-29T19:35:33.120Z"},{"source":"EPSS","status":"available","checkedAt":"2026-10-29T19:35:35.987Z","attemptedAt":"2026-10-29T19:35:35.987Z"}],"evidence":[{"source":"ENISA EUVD","id":"EUVD-2026-107151","url":"https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-107151","modified":"Oct 21, 2026, 8:56:55 AM","score":3.7,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N","checkedAt":"2026-10-29T19:35:33.120Z"},{"source":"GitHub Advisory Database","id":"GHSA-mh74-9w87-h7vx","url":"https://github.com/advisories/GHSA-mh74-9w87-h7vx","modified":"2026-10-21T09:30:35Z","score":3.7,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N","checkedAt":"2026-10-29T19:35:34.806Z"},{"source":"NVD","id":"CVE-2026-35501","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-35501","modified":"2026-10-29T19:17:21.600","score":3.7,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N","checkedAt":"2026-10-29T19:35:34.812Z"},{"source":"FIRST EPSS","id":"CVE-2026-35501","url":"https://www.first.org/epss/","probability":0.00111,"percentile":0.01309,"date":"2026-10-29","checkedAt":"2026-10-29T19:35:35.987Z"}],"aiSummary":{"text":"Unbound versions 1.0.1 to 1.26.1 are vulnerable to a bypass of a configured island trust anchor when an attacker-controlled NSEC record is used. An attacker with a forged NSEC reply can trick Unbound into treating the trust island as insecure. This occurs due to improper validation of the NSEC response.","model":"@cf/meta/llama-3.3-70b-instruct-fp8-fast","generatedAt":"2026-10-30T09:49:43.806Z","sources":[{"name":"CVE","url":"https://www.cve.org/CVERecord?id=CVE-2026-35501"}]}}