VulnSocial

CVE-2026-12221General

LOWCVSS 7.3 · HIGH

Exploit discussion active in current signal (1 latest mentions)

Immediate actions

  • Prioritize remediation for affected systems immediately
  • Hunt for exploitation attempts and persistence artifacts
  • Increase monitoring for publicly documented tradecraft
  • Track advisory updates for patch or workaround availability

Recommended action window: High priority (within 72h)

NVD description

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 and is working on a patch to fix it.

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3.5/ 10 priority

Sources & remediation

Other references
Weakness type (CWE)
CWE-119CWE-121

Priority

LOW

Exploitation

NONE

PoC

YES

Patch

NONE

Momentum

STABLE

Threat summary

  • Public PoC and exploit tooling are both present
  • 3 mentions across 3 observed days
  • Momentum state: stable

What's happening

  • Exploit tool or code specified in 1 signal
  • PoC mentioned or linked in 1 signal
  • Technical details provided in 1 signal
  • General: 1 classified signal
  • Disclosure: 1 classified signal
  • Peaked 2d ago at 1 mentions (2026-06-14); latest day: 1
  • 3 total mentions across 3 days

Deep dive

Activity timeline3 mentions / 3d
00111Mentions · 2026-06-14: 1Mentions · 2026-06-15: 1Mentions · 2026-07-23: 1PoC Mentioned / Linked · 2026-07-23: 1Exploit Tool / Code · 2026-07-23: 1Technical Details · 2026-06-15: 106-1406-1507-23
Signal classification3 categories
General
133.3%
Disclosure
133.3%
PoC
133.3%
Referenced assets3 URLs
Classification over time
DateTotalLabels
2026-06-141
General1
2026-06-151
Disclosure1
2026-07-231
PoC1
Full discourse3 posts
  • MalwareObserver@MalwareObserver
    PoC

    🐛 VULNERABILITIES CVE Notify: 🚨 [CVE-2026-12221](http://cdn2.v50to.cc/T46U/T46U_mod_upgrade_Upgrade_chunk_stack_overflow.zip) A v... http://cdn2.v50to.cc/T46U/T46U_mod_upgrade_Upgrade_chunk_stack_overflow.zip #Vulnerability #CVE #ZeroDay

    Post summary

    The post shares a downloadable ZIP that likely contains a proof‑of‑concept exploit for CVE‑2026‑12221, but offers no technical details, patch information, or evidence of active exploitation.

    0000038
    13 followersView on X
  • Vulmon Vulnerability Feed@VulmonFeeds
    Disclosure

    CVE-2026-12221 Stack-Based Buffer Overflow in Yealink SIP-T46U Firmware Chunk Upload Handler https://vulmon.com/vulnerabilitydetails?qid=CVE-2026-12221

    Post summary

    The snippet presents a disclosure of a stack-based buffer overflow vulnerability in Yealink SIP-T46U firmware, without any PoC, exploit, or mitigation details.

    0000037
    4.0K followersView on X
  • VulDB 🛡@vuldb
    General

    The severity is increased for this new vulnerability affecting Yealink SIP-T46U (CVE-2026-12221) https://vuldb.com/vuln/370864

    Post summary

    The post notes an increased severity for a new Yealink SIP-T46U vulnerability but offers no technical specifics, PoC, or exploit details.

    0000060
    2.2K followersView on X

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