{"id":"CVE-2026-12632","title":"Out-of-bounds read in Zephyr PTP message parsing from unvalidated message type","summary":"Zephyr's Precision Time Protocol receive handler ptp_msg_post_recv() in subsys/net/lib/ptp/msg.c takes the 4-bit message type straight off the wire via ptp_msg_type() (msg->header.type_major_sdo_id & 0xF, range 0-15) and uses it to index…","severity":"medium","cvss":6.5,"cvssVector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","cvssSource":"cna","cwe":["CWE-125"],"vendor":"zephyrproject","product":"zephyr","affected":["zephyr >= 3.7.0 < 4.3.2","zephyr >= 4.4.0 < 4.4.2"],"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"partial","timestamp":"2026-08-19T13:21:36.731868Z"},"published":"2026-08-18","updated":"2026-11-04","sourceUpdated":"2026-11-04T04:59:36.437Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-12632","references":[{"url":"https://github.com/zephyrproject-rtos/zephyr/commit/30dabd4c2f2e3641732c00111cd80b5c524c0136","label":"Fix commit"},{"url":"https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-frjr-h396-7wh4","label":"GHSA-frjr-h396-7wh4"}],"tags":["cve.org"],"epss":0.00285,"epssPercentile":0.21114,"ingestedAt":"2026-11-05T20:33:06.704Z","slug":"CVE-2026-12632","body":"## Overview\n\nZephyr's Precision Time Protocol receive handler ptp_msg_post_recv() in subsys/net/lib/ptp/msg.c takes the 4-bit message type straight off the wire via ptp_msg_type() (msg->header.type_major_sdo_id & 0xF, range 0-15) and uses it to index the msg_size[] table. That table only defines entries up to PTP_MSG_MANAGEMENT (0xD), giving it ARRAY_SIZE == 14. Before the fix there was no upper-bound check, so the undefined types 0xE and 0xF indexed one or two int slots past the end of the array — an out-of-bounds read of adjacent read-only data.\n\nThe out-of-bounds value is then reused as a length: it gates msg_size[type] > cnt, and when it is small or negative it makes cnt - msg_size[type] a large positive budget passed to msg_tlv_post_recv(), whose TLV loop then walks the message suffix past the received bytes, performing further out-of-bounds reads and in-place byte-swap writes on memory beyond the message slab.\n\nThe defect is reached directly from the network: ptp_port_event_gen() in subsys/net/lib/ptp/port.c reads a PTP frame with ptp_transport_recv() and calls ptp_msg_post_recv() with the attacker-chosen type. PTP uses UDP multicast or raw Ethernet (0x88F7) and is unauthenticated, so any host on the same link can trigger the indexing on a CONFIG_PTP-enabled node with no preconditions.\n\nThe reliably reproducible impact is a denial of service (fault/crash); a limited memory-corruption path exists but depends on the build-specific value adjacent to msg_size[], which the attacker cannot tune. The fix rejects type >= ARRAY_SIZE(msg_size) with -EBADMSG before any indexing.\n\n## Affected\n\n- `zephyr >= 3.7.0 < 4.3.2`\n- `zephyr >= 4.4.0 < 4.4.2`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":36,"depthScoreParts":{"impact":35.8,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}