{"answers":{"affected":"It affects 1 product.","exploited":"There is no known exploitation of CVE-2026-55717 in the wild and no public exploit code.","fix":"Upgrade to a fixed version.","what":"CVE-2026-55717 is a medium-severity vulnerability in Nlnetlabs Unbound, published on 22 Jul 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-2026-55717 and fix it if it is affected.\n\nWhat it is: CVE-2026-55717 is a medium-severity vulnerability in Nlnetlabs Unbound, published on 22 Jul 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-2026-55717 in the wild and no public exploit code.\n\nAffected product: Nlnetlabs Unbound. 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-2026-55717/ (Markdown: https://insights.sbomify.com/CVE-2026-55717/index.md)","id":"CVE-2026-55717","markdown":"https://insights.sbomify.com/CVE-2026-55717/index.md","name":"CVE-2026-55717","record":{"aliases":["ALPINE-CVE-2026-55717","AZL-92946","DEBIAN-CVE-2026-55717","ECHO-cac0-04fd-234b","GHSA-9vcf-h83p-jghm","UBUNTU-CVE-2026-55717"],"analysis":{"component_type":"server_software","fix_type":"upgrade","impacts":["denial_of_service"],"network_reachable":"yes","non_default_config":true,"product_category":"DNS resolver","requires_auth":"none","summary":"Remote attackers can crash the Unbound DNS server by exploiting a NULL pointer dereference in the serve-expired and response-ip CNAME redirect logic.","user_interaction":"not_required","vuln_class":"null_dereference"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"NLnet Labs","cpe":[{"product":"unbound","vendor":"nlnetlabs"}],"cvss":{"score":5.9,"severity":"medium","source":"cna","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H","version":"3.1"},"cwes":[{"id":"CWE-476","name":"NULL Pointer Dereference"}],"description":"In NLnet Labs Unbound 1.10.0 up to and including 1.25.1, when 'serve-expired: yes' is set together with a 'response-ip: \u003cnet\u003e redirect' /'response-ip-data: \u003cnet\u003e CNAME \u003ctarget\u003e' rule (or the RPZ 'rpz-cname-override' equivalent), a remote client who controls any delegated domain can crash the daemon. The serve-expired-client-timeout callback runs a two-pass loop to chase the respip-generated CNAME alias; on the second pass it resets 'alias_rrset' but not 'partial_rep'. Later, this inconsistency leads to a NULL pointer dereference and an eventual crash. A malicious actor can exploit the vulnerability by controlling any zone that replies with an A/AAAA record that falls inside the configured response-ip/rpz subnet. By delaying the answer when the previous record has expired, the vulnerable path of 'serve-expired-client-timeout' is taken leading to denial of service via the server crash.","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":"'serve-expired-client-timeout' and 'response-ip' CNAME redirect could lead to a crash","id":"CVE-2026-55717","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":"nlnetlabs:unbound","products":["nlnetlabs:unbound"],"type":"null_dereference","year":"2026"},"n_packages":0,"n_references":1,"next":{"headline":"SQL Injection in StoneFly Storage Concentrator","id":"CVE-2026-55721"},"packages":[],"prev":{"headline":"Privacy/configuration issue when adding local data in views through 'unbound-control'","id":"CVE-2026-55708"},"products":["Unbound"],"published":"2026-07-22","related":[{"cvss_score":9.1,"headline":"Heap buffer overflow and possible Remote Code Execution when digesting DNSKEY","id":"CVE-2026-81642","kev_date_added":null,"published":"2026-09-16"},{"cvss_score":9.1,"headline":"Possible arbitrary code execution during DNSSEC validation","id":"CVE-2026-33278","kev_date_added":null,"published":"2026-05-20"},{"cvss_score":8.7,"headline":"Heap overflow with multiple NSID, COOKIE, PADDING EDNS options","id":"CVE-2026-42944","kev_date_added":null,"published":"2026-05-20"},{"cvss_score":8.7,"headline":"Crash during DNSSEC validation of malicious content","id":"CVE-2026-42959","kev_date_added":null,"published":"2026-05-20"},{"cvss_score":8.4,"headline":"CNAME synthesis could lead to heap corruption","id":"CVE-2026-82717","kev_date_added":null,"published":"2026-09-16"},{"cvss_score":7.5,"headline":"Possible heap buffer overflow during DNSSEC canonicalization","id":"CVE-2026-81634","kev_date_added":null,"published":"2026-09-16"},{"cvss_score":7.5,"headline":"Remote DNS-over-QUIC denial of service due to `quic-size` budget bypass","id":"CVE-2026-32665","kev_date_added":null,"published":"2026-07-22"}],"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":"2026-07-22","vendors":["NLnet Labs"]},"summary":"Remote attackers can crash the Unbound DNS server by exploiting a NULL pointer dereference in the serve-expired and response-ip CNAME redirect logic.","url":"https://insights.sbomify.com/CVE-2026-55717/"}