{"answers":{"affected":"","exploited":"There is no known exploitation of CVE-2026-5856 in the wild and no public exploit code.","fix":"No fix has been published for CVE-2026-5856 yet. Limit exposure of the affected software until one is available.","what":"CVE-2026-5856 is a high-severity vulnerability in Contiki-NG, published on 6 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2026-5856 and fix it if it is affected.\n\nWhat it is: CVE-2026-5856 is a high-severity vulnerability in Contiki-NG, published on 6 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.\nExploitation: There is no known exploitation of CVE-2026-5856 in the wild and no public exploit code.\n\nAffected product: Contiki-NG. 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-2026-5856/ (Markdown: https://insights.sbomify.com/CVE-2026-5856/index.md)","id":"CVE-2026-5856","markdown":"https://insights.sbomify.com/CVE-2026-5856/index.md","name":"CVE-2026-5856","record":{"aliases":["GHSA-8m55-g479-xj8c"],"analysis":{"component_type":"iot_embedded","fix_type":"patch","impacts":["data_read","denial_of_service"],"network_reachable":"adjacent_or_local","non_default_config":false,"product_category":"Contiki-NG OS","requires_auth":"none","summary":"An attacker can trigger an out-of-bounds read in the Contiki-NG DNS resolver, potentially disclosing memory contents or causing a denial of service.","user_interaction":"not_required","vuln_class":"information_disclosure"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"VulnCheck","cpe":[],"cvss":{"score":7.1,"severity":"high","source":"cna","vector":"CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:L/SC:N/SI:N/SA:N","version":"4.0"},"cwes":[{"id":"CWE-125","name":"Out-of-bounds Read"}],"description":"Contiki-NG's DNS/mDNS resolver skip_name() in os/services/resolv/resolv.c walks DNS wire-format name labels with no packet-boundary check, and the caller in newdata() invokes it in a loop iterating nquestions times from the attacker-controlled DNS header before validating the transaction ID. An attacker who sets nquestions higher than the number of complete questions present causes skip_name() to walk past the UDP packet buffer, and the returned pointer is cast to struct dns_answer * for further memory reads. On builds with RESOLV_CONF_SUPPORTS_MDNS enabled, any peer on the local segment can trigger the read unauthenticated via a multicast UDP 5353 packet with no outstanding query required; on standard DNS builds an attacker who can inject a UDP response from port 53 during an outstanding query can trigger the same read. Impact is out-of-bounds read of uip_buf and adjacent memory, disclosing memory contents or crashing the resolver.","ecosystems":[],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"none_known"},"has_fix":false,"headline":"Contiki-NG DNS/mDNS Resolver Out-of-Bounds Read via Unchecked skip_name Traversal Before Transaction-ID Validation","id":"CVE-2026-5856","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":null,"products":[],"type":"information_disclosure","year":"2026"},"n_packages":0,"n_references":3,"next":{"headline":"Contiki-NG MQTT Client Out-of-Bounds Write in PUBLISH Topic Parser via Persistent State Between TCP Segments","id":"CVE-2026-5857"},"packages":[],"prev":{"headline":"Contiki-NG LwM2M TLV Parser Out-of-Bounds Read via Unchecked Buffer Length in lwm2m_tlv_read","id":"CVE-2026-5855"},"products":["Contiki-NG"],"published":"2026-08-06","related":[],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"},{"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":"2026-08-14","vendors":["Contiki-NG"]},"summary":"An attacker can trigger an out-of-bounds read in the Contiki-NG DNS resolver, potentially disclosing memory contents or causing a denial of service.","url":"https://insights.sbomify.com/CVE-2026-5856/"}