{"answers":{"affected":"It affects 1 product.","exploited":"There is no known exploitation of CVE-2026-77955 in the wild and no public exploit code.","fix":"Upgrade to a fixed version.","what":"CVE-2026-77955 is a medium-severity vulnerability in Nlnetlabs Unbound, published on 16 Sep 2026. An attacker needs administrator access to exploit it, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2026-77955 and fix it if it is affected.\n\nWhat it is: CVE-2026-77955 is a medium-severity vulnerability in Nlnetlabs Unbound, published on 16 Sep 2026. An attacker needs administrator access to exploit it, with no action from the victim.\nExploitation: There is no known exploitation of CVE-2026-77955 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-2026-77955/ (Markdown: https://insights.sbomify.com/CVE-2026-77955/index.md)","id":"CVE-2026-77955","markdown":"https://insights.sbomify.com/CVE-2026-77955/index.md","name":"CVE-2026-77955","record":{"aliases":["AZL-101715","DEBIAN-CVE-2026-77955","ECHO-d671-fe45-3358","GHSA-w62x-5q5r-fgmp","UBUNTU-CVE-2026-77955"],"analysis":{"component_type":"server_software","fix_type":"upgrade","impacts":["data_read","security_bypass"],"network_reachable":"yes","non_default_config":true,"product_category":"DNS resolver","requires_auth":"high_privilege","summary":"Attackers can serve tampered DNS zone data before integrity checks complete, bypassing ZONEMD verification in Unbound when specific configurations are enabled.","user_interaction":"not_required","vuln_class":"security_feature_bypass"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"NLnet Labs","cpe":[{"product":"unbound","vendor":"nlnetlabs"}],"cvss":{"score":4.4,"severity":"medium","source":"cna","vector":"CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:H/A:N","version":"3.1"},"cwes":[{"id":"CWE-345","name":"Insufficient Verification of Data Authenticity"}],"description":"In NLnet Labs Unbound 1.13.2 up to and including 1.26.1, a vulnerability in ZONEMD configured zones (zonemd-check: yes) which are located below (but not at) a trust anchor allow for an attack window where (tampered with) zone contents are served (or stored to disk) prior to the ZONEMD integrity check. This is caused by the needed DS/DNSKEY asynchronous resolution that needs to happen before the ZONEMD check completes. If a zonefile is written to disk (zonefile: option) while the ZONEMD check failed, the tampered data are reloaded on startup and available until ZONEMD verification concludes again. If verification fails, the data is not served any more but still persists on disk for future reloads.","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":"Possible ZONEMD verification bypass window","id":"CVE-2026-77955","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":"nlnetlabs:unbound","products":["nlnetlabs:unbound"],"type":"security_feature_bypass","year":"2026"},"n_packages":0,"n_references":1,"next":{"headline":"EEx template evaluation of prompt content in AshAi enables remote code execution","id":"CVE-2026-77956"},"packages":[],"prev":{"headline":"RPC error handler fails open in AshTypescript, disclosing unredacted errors","id":"CVE-2026-77950"},"products":["Unbound"],"published":"2026-09-16","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":"2026-09-16","vendors":["NLnet Labs"]},"summary":"Attackers can serve tampered DNS zone data before integrity checks complete, bypassing ZONEMD verification in Unbound when specific configurations are enabled.","url":"https://insights.sbomify.com/CVE-2026-77955/"}