{"id":"CVE-2026-10652","summary":"Out-of-bounds read in Zephyr DNS resolver TXT/SRV record parsing (unvalidated `rdlength`)","details":"Zephyr's DNS resolver (subsys/net/lib/dns) parses resource records from DNS responses in dns_unpack_answer(), which validated only the fixed RR header (type, class, TTL, rdlength) and accepted any attacker-declared rdlength, including one extending past the end of the received datagram. The TXT and SRV consumers in dns_validate_record() (resolve.c) then read up to rdlength bytes (clamped only to a record-type maximum such as DNS_MAX_TEXT_SIZE, default 64, not to the packet) from the receive buffer via memcpy without their own bounds check, and pass the result to the application's resolve callback. A malicious or spoofed DNS server, an on-path attacker forging UDP DNS replies, or (with mDNS/LLMNR enabled) any LAN node can craft a truncated TXT or SRV response that causes an out-of-bounds read of adjacent receive-pool memory; the disclosed stale bytes (residual contents of prior DNS packets / uninitialized pool memory) are returned to the application as TXT/SRV record contents, an information leak, and may in some configurations cross the allocation boundary and fault, causing a denial of service. The read is bounded (~64 bytes for TXT, ~6 for SRV) and read-only (no write). The fix rejects any record whose declared rdata extends past dns_msg-\u003emsg_size at the single chokepoint in dns_unpack_answer(). Affected: v4.3.0 and v4.4.0.","aliases":["GHSA-3jxq-xx8g-q8j2"],"modified":"2026-10-17T02:30:23.679275778Z","published":"2026-06-30T15:50:46.510Z","database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/10xxx/CVE-2026-10652.json","cna_assigner":"zephyr","cwe_ids":["CWE-125"]},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/10xxx/CVE-2026-10652.json"},{"type":"ADVISORY","url":"https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-3jxq-xx8g-q8j2"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-10652"},{"type":"FIX","url":"https://github.com/zephyrproject-rtos/zephyr/commit/58b46c81c6796dac4dc7391f32ba006474f94dc8"},{"type":"PACKAGE","url":"https://github.com/zephyrproject-rtos/zephyr"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/zephyrproject-rtos/zephyr","events":[{"introduced":"3568e1b6d5cdd51a6b964a2a1d6d29200fea2056"},{"fixed":"75f67d766726351b30199f9a2bf55803d717a3be"},{"introduced":"684c9e8f32e4373a21098559f748f06915f950c9"},{"fixed":"1f6485eca25431b5ff27ce9a754218c9e559bbbb"}],"database_specific":{"source":"AFFECTED_FIELD","extracted_events":[{"introduced":"4.3.0"},{"fixed":"4.3.1"},{"introduced":"4.4.0"},{"fixed":"4.4.1"}]}}],"versions":["v4.3.1-rc1","v4.4.1-rc1","v4.4.0","v4.3.0"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-10652.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:L"}]}