CVE-2026-12220

CVE-2026-12220 is a high-severity vulnerability with a CVSS 3.x base score of 8.0. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-119.

Key facts

Description

A vulnerability has been found in Yealink SIP-T46U 108.86.0.118. This affects the function mod_upgrade.SparePartsUpload of the file /api/upgrade/accupgradebychunk of the component Firmware Chunk Upload handler. Such manipulation of the argument uid leads to stack-based buffer overflow. The attack can only be initiated within the local network. The exploit has been disclosed to the public and may be used. The vendor was contacted early about this disclosure and is working on a patch to fix it.

Frequently asked questions

What is CVE-2026-12220?
A vulnerability has been found in Yealink SIP-T46U 108.86.0.118. This affects the function mod_upgrade.SparePartsUpload of the file /api/upgrade/accupgradebychunk of the component Firmware Chunk Upload handler. Such manipulation of the argument uid leads to stack-based buffer overflow. The attack can only be initiated within the local network. The exploit has been disclosed to the public and may be used. The vendor was contacted early about this disclosure and is working on a patch to fix it.
How severe is CVE-2026-12220?
CVE-2026-12220 has a CVSS 3.x base score of 8.0, rated high severity. It is exploitable over an adjacent network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-12220 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (29th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-12220?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2026-12220 have an EU (EUVD) identifier?
Yes. CVE-2026-12220 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-36693.
When was CVE-2026-12220 published?
CVE-2026-12220 was published on 2026-06-15 and last updated on 2026-06-27.

References

Other CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer) vulnerabilities

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