{"document":{"category":"csaf_vex","csaf_version":"2.0","title":"CVE-2026-12221: Yealink SIP-T46U Firmware Chunk Upload upgrade sprintf stack-based overflow","publisher":{"category":"vendor","name":"HarborGuard Database","namespace":"https://database.harborguard.co"},"tracking":{"id":"CVE-2026-12221","status":"final","version":"1","initial_release_date":"2026-06-15T05:00:10.661Z","current_release_date":"2026-06-15T05:00:10.661Z","revision_history":[{"date":"2026-06-15T05:00:10.661Z","number":"1","summary":"Initial machine-readable export from HarborGuard."}]},"distribution":{"tlp":{"label":"WHITE"},"text":"Public CVE data; freely redistributable."},"notes":[{"category":"description","text":"A vulnerability was found in Yealink SIP-T46U 108.86.0.118. This impacts the function sprintf of the file /api/upgrade/upgrade of the component Firmware Chunk Upload Handler. Performing a manipulation of the argument uid/start_offset results in stack-based buffer overflow. The attack needs to be approached within the local network. The exploit has been made public and could be used. The vendor was contacted early about this disclosure but did not respond in any way.","title":"CVE description"}],"references":[{"category":"self","summary":"CVE-2026-12221 on HarborGuard Database","url":"https://database.harborguard.co/cve/CVE-2026-12221"},{"category":"external","summary":"CVE Record","url":"https://www.cve.org/CVERecord?id=CVE-2026-12221"},{"category":"external","summary":"VDB-370864 | Yealink SIP-T46U Firmware Chunk Upload upgrade sprintf stack-based overflow","url":"https://vuldb.com/vuln/370864"},{"category":"external","summary":"VDB-370864 | CTI Indicators (IOB, IOC, IOA)","url":"https://vuldb.com/vuln/370864/cti"},{"category":"external","summary":"CVE-2026-12221 | CVE Analysis and Report","url":"https://vuldb.com/cve/CVE-2026-12221"},{"category":"external","summary":"Submit #834207 | yealink T46U 108.86.0.118 Stack-based Buffer Overflow","url":"https://vuldb.com/submit/834207"},{"category":"external","summary":"cdn2.v50to.cc","url":"http://cdn2.v50to.cc/T46U/T46U_mod_upgrade_Upgrade_chunk_stack_overflow.zip"}]},"product_tree":{"branches":[{"category":"vendor","name":"Yealink","branches":[{"category":"product_name","name":"SIP-T46U","branches":[{"category":"product_version","name":"108.86.0.118","product":{"name":"Yealink SIP-T46U 108.86.0.118","product_id":"CSAFPID-1","product_identification_helper":{"cpe":"cpe:2.3:a:yealink:sip-t46u:108.86.0.118:*:*:*:*:*:*:*"}}}]}]}]},"vulnerabilities":[{"cve":"CVE-2026-12221","title":"Yealink SIP-T46U Firmware Chunk Upload upgrade sprintf stack-based overflow","notes":[{"category":"description","text":"A vulnerability was found in Yealink SIP-T46U 108.86.0.118. This impacts the function sprintf of the file /api/upgrade/upgrade of the component Firmware Chunk Upload Handler. Performing a manipulation of the argument uid/start_offset results in stack-based buffer overflow. The attack needs to be approached within the local network. The exploit has been made public and could be used. The vendor was contacted early about this disclosure but did not respond in any way.","title":"CVE description"}],"product_status":{"known_affected":["CSAFPID-1"]},"scores":[{"cvss_v4":{"version":"4.0","vectorString":"CVSS:4.0/AV:A/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P","baseScore":8.6,"baseSeverity":"HIGH"},"products":["CSAFPID-1"]}],"remediations":[{"category":"none_available","details":"No fixed version is published yet. Monitor the upstream advisory.","product_ids":["CSAFPID-1"]}]}]}