{"answers":{"affected":"","exploited":"There is no known exploitation of CVE-2026-12633 in the wild and no public exploit code.","fix":"No fix has been published for CVE-2026-12633 yet. Limit exposure of the affected software until one is available.","what":"CVE-2026-12633 is a high-severity memory corruption vulnerability in zephyrproject zephyr, published on 19 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-2026-12633 and fix it if it is affected.\n\nWhat it is: CVE-2026-12633 is a high-severity memory corruption vulnerability in zephyrproject zephyr, published on 19 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-2026-12633 in the wild and no public exploit code.\n\nAffected product: zephyrproject zephyr. 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-2026-12633/ (Markdown: https://insights.sbomify.com/CVE-2026-12633/index.md)","id":"CVE-2026-12633","markdown":"https://insights.sbomify.com/CVE-2026-12633/index.md","name":"CVE-2026-12633","record":{"aliases":["GHSA-h5m5-hm6j-cgpf"],"analysis":{"component_type":"operating_system","fix_type":"patch","impacts":["denial_of_service","data_modify"],"network_reachable":"adjacent_or_local","non_default_config":true,"product_category":"Zephyr RTOS","requires_auth":"none","summary":"An attacker on the same network link can cause a denial of service and memory corruption in Zephyr RTOS by sending a crafted IPv6 Router Advertisement.","user_interaction":"not_required","vuln_class":"memory_corruption"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"zephyr","cpe":[],"cvss":{"score":8.1,"severity":"high","source":"cna","vector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H","version":"3.1"},"cwes":[{"id":"CWE-787","name":"Out-of-bounds Write"}],"description":"The IPv6 neighbor-discovery code in subsys/net/ip/ipv6_nbr.c processes the 6LoWPAN Context Option (6CO, RFC 6775) carried inside ICMPv6 Router Advertisements. In handle_ra_6co() the 8-bit context_len field is taken directly from the packet and was never bounded to the RFC maximum of 128. The function computes context-\u003econtext_len / 8 and then performs memset(context-\u003eprefix + context_len, 0, sizeof(context-\u003eprefix) - context_len), where context-\u003eprefix is a fixed 16-byte array.\n\nWith context_len between 136 and 255 (and the option length field set to 3, which the pre-fix validation accepts), context_len / 8 evaluates to 17..31, so the memset length 16 - context_len/8 underflows the unsigned size_t argument to roughly SIZE_MAX. This produces an unbounded out-of-bounds memset that zeroes kernel memory well past the 6lo context structure.\n\nThe defect is reachable from unauthenticated, link-local input: any host on the same link can send a crafted Router Advertisement with a 6CO option. The RA handler validates only the option length field before calling handle_ra_6co(), so a single packet triggers the wild write. The code is compiled when CONFIG_NET_6LO_CONTEXT is enabled.\n\nThe impact is a reliable remote (adjacent) denial of service via memory corruption, with collateral integrity loss as the memset zeroes contiguous memory before the system faults. Router Advertisements are link-scoped and not forwarded, so the attacker must be on the same link (AV:A). The fix rejects any context_len greater than 128 before the length computation.","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":"Out-of-bounds write in IPv6 6LoWPAN Context Option handling via unauthenticated Router Advertisement","id":"CVE-2026-12633","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":null,"products":[],"type":"memory_corruption","year":"2026"},"n_packages":0,"n_references":2,"next":{"headline":"Out-of-bounds stack write in the settings NVS backend from over-reported nvs_read length","id":"CVE-2026-12634"},"packages":[],"prev":{"headline":"Out-of-bounds read in Zephyr PTP message parsing from unvalidated message type","id":"CVE-2026-12632"},"products":["zephyr"],"published":"2026-08-19","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":"2026-08-20","vendors":["zephyrproject"]},"summary":"An attacker on the same network link can cause a denial of service and memory corruption in Zephyr RTOS by sending a crafted IPv6 Router Advertisement.","url":"https://insights.sbomify.com/CVE-2026-12633/"}