Quick answers
- Is CVE-2026-12221 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-12221 being exploited in the wild.
- How severe is CVE-2026-12221?
- High severity, with a CVSS score of 8, published 15 June 2026.
- Which products and versions are affected?
- Yealink SIP-T46U 108.86.0.118.
- Is there a fix for CVE-2026-12221?
- No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
- How is CVE-2026-12221 attacked?
- It is attacked from the adjacent network, in a network appliance.
- Am I affected by CVE-2026-12221?
- Check whether you run Yealink SIP-T46U at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
Technical details
A stack-based buffer overflow vulnerability exists in the Yealink SIP-T46U firmware version 108.86.0.118. The flaw is located within the 'sprintf' function call in the '/api/upgrade/upgrade' file, specifically within the Firmware Chunk Upload Handler component. An attacker can trigger the overflow by manipulating the 'uid' or 'start_offset' arguments during a firmware upload request. Exploitation requires access to the adjacent network and low-level privileges. Successful exploitation could lead to arbitrary code execution or a device crash. A public exploit is reportedly available, and the vendor has not yet provided a patch.
Affected products
- Yealink SIP-T46U 108.86.0.118
Timeline
- 2026-06-15: disclosed
- 2026-06-15: advisory: NVD publication date