{"id":"CVE-2026-10652","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-10652","generatedAt":"2026-10-28T00:18:14.469Z","title":"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…","description":"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->msg_size at the single chokepoint in dns_unpack_answer(). Affected: v4.3.0 and v4.4.0.","published":"2026-06-30T17:16:20.000Z","lastModified":"2026-10-25T21:10:01.000Z","status":"Analyzed","sourceIdentifier":"vulnerabilities@zephyrproject.org","cvss":{"version":"3.1","score":7.4,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:H"},"cwe":["CWE-125"],"affected":["zephyrproject/zephyr"],"epss":{"score":0.00415,"percentile":0.35533,"date":"2026-10-26","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"high","text":"High impact if exploited, but EPSS currently rates exploitation as unlikely (0.41%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit."},"changes":[],"references":[{"url":"https://github.com/zephyrproject-rtos/zephyr/commit/58b46c81c6796dac4dc7391f32ba006474f94dc8","tags":["Patch"],"source":"vulnerabilities@zephyrproject.org"},{"url":"https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-3jxq-xx8g-q8j2","tags":["Exploit","Patch","Vendor Advisory"],"source":"vulnerabilities@zephyrproject.org"},{"url":"https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-3jxq-xx8g-q8j2","tags":["Exploit","Patch","Vendor Advisory"],"source":"134c704f-9b21-4f2e-91b3-4a467353bcc0"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-10652","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}