| Titel | yealink T46U 108.86.0.118 Stack-based Buffer Overflow |
|---|
| Beschreibung | Yealink T46U phone firmware `x.x.x.x` contains a stack buffer overflow vulnerability in the firmware chunk upload handler of `fcgiserver`. The vulnerable endpoint is:
```text
POST /api/upgrade/upgrade
```
The handler accepts chunk upload parameters such as `uid` and `start_offset`. These values are checked as decimal strings but are not length-limited before being concatenated into a fixed-size stack path buffer with `sprintf()`.
poc
POST /api/upgrade/beforeupgrade?p=Upgrade&t=<timestamp> HTTP/1.1
...
POST /api/upgrade/upgrade?p=Upgrade&t=<timestamp> HTTP/1.1
Content-Type: application/x-www-form-urlencoded; charset=UTF-8
uType=chunk&phase=upload&uid=<long-numeric-string>&start_offset=0
|
|---|
| Quelle | ⚠️ http://cdn2.v50to.cc/T46U/T46U_mod_upgrade_Upgrade_chunk_stack_overflow.zip |
|---|
| Benutzer | CookedMelon (UID 52513) |
|---|
| Einreichung | 20.05.2026 17:40 (vor 5 Monaten) |
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| Moderieren | 14.06.2026 15:54 (25 days later) |
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| Status | Akzeptiert |
|---|
| VulDB Eintrag | 370864 [Yealink SIP-T46U 108.86.0.118 Firmware Chunk Upload /api/upgrade/upgrade sprintf uid/start_offset Pufferüberlauf] |
|---|
| Punkte | 20 |
|---|