{"id":"CVE-2026-10672","title":"Unterminated URI buffer causes out-of-bounds read in LwM2M firmware pull (Package URI)","summary":"subsys/net/lib/lwm2m/lwm2m_pull_context.c copied the firmware-update Package URI into a fixed static buffer (context.uri, size CONFIG_LWM2M_SWMGMT_PACKAGE_URI_LEN, default 128) with memcpy(context.uri, uri, LWM2M_PACKAGE_URI_LEN), copyin…","severity":"high","cvss":8.2,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:L","cvssSource":"cna","cwe":["CWE-125"],"vendor":"zephyrproject","product":"zephyr","affected":["zephyr >= 3.0.0 < 4.3.1","zephyr >= 4.4.0 < 4.4.1"],"ssvc":{"exploitation":"poc","automatable":"yes","technicalImpact":"partial","timestamp":"2026-07-14T15:28:04.126168Z"},"exploitAvailable":true,"published":"2026-07-14","updated":"2026-10-15","sourceUpdated":"2026-10-15T22:10:15.606Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-10672","references":[{"url":"https://github.com/zephyrproject-rtos/zephyr/commit/99a164df5cea5af76e32b57c6d51854f018969a2","label":"Fix commit"},{"url":"https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-rf6j-4mpp-j9mf","label":"GHSA-rf6j-4mpp-j9mf"}],"tags":["cve.org","exploit-available"],"epss":0.00579,"epssPercentile":0.46324,"exploits":{"github":1,"githubRepos":["https://github.com/Hunt-Benito/zephyr-lwm2m-firmware-update-oob-read-cve-2026-10672-truncated-package-uri"],"checkedAt":"2026-10-15T22:49:00.743Z"},"ingestedAt":"2026-10-15T22:48:25.571Z","slug":"CVE-2026-10672","body":"## Overview\n\nsubsys/net/lib/lwm2m/lwm2m_pull_context.c copied the firmware-update Package URI into a fixed static buffer (context.uri, size CONFIG_LWM2M_SWMGMT_PACKAGE_URI_LEN, default 128) with memcpy(context.uri, uri, LWM2M_PACKAGE_URI_LEN), copying exactly the destination size with no length validation. The Firmware-Update object stores the server-supplied Package URI (/5/0/1) in a 255-byte buffer, so a LwM2M management server (or an on-path attacker on a session lacking strong DTLS) can WRITE a URI of 128-254 characters; only the first 128 bytes are then copied into context.uri with no NUL terminator. That buffer is subsequently consumed as a C string by http_parser_parse_url(context.uri, strlen(context.uri), ...), strlen-based CoAP URI-path/PROXY-URI option appends, and lwm2m_parse_peerinfo(), causing an out-of-bounds read of adjacent static memory. The over-read bytes are appended to outbound CoAP requests (information disclosure of adjacent device memory to the server/proxy) and can crash the device (denial of service). The vulnerable copy was introduced by the pull-context refactor (first released in v3.0.0) and is present through v4.4.0; the default-on CONFIG_LWM2M_FIRMWARE_UPDATE_PULL_SUPPORT path is affected. The fix adds a strlen(uri) >= sizeof(context.uri) check returning -ENOMEM and switches to strcpy(), guaranteeing a bounded, NUL-terminated buffer.\n\n## Affected\n\n- `zephyr >= 3.0.0 < 4.3.1`\n- `zephyr >= 4.4.0 < 4.4.1`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"midnight","depthScore":57,"depthScoreParts":{"impact":45.1,"likelihood":0.1,"exploitation":12,"ransomware":0},"changes":[]}