CVE-2021-33500
First published: Fri May 21 2021(Updated: )
PuTTY before 0.75 on Windows allows remote servers to cause a denial of service (Windows GUI hang) by telling the PuTTY window to change its title repeatedly at high speed, which results in many SetWindowTextA or SetWindowTextW calls. NOTE: the same attack methodology may affect some OS-level GUIs on Linux or other platforms for similar reasons.
Credit: cve@mitre.org
| Affected Software | Affected Version | How to fix |
|---|---|---|
| PuTTY | <0.75 | |
| Microsoft Windows |
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Reference Links
Frequently Asked Questions
What is the vulnerability ID for this PuTTY vulnerability?
The vulnerability ID is CVE-2021-33500.
What is the severity of CVE-2021-33500 vulnerability?
The severity of CVE-2021-33500 vulnerability is high with a severity value of 7.5.
How does PuTTY before 0.75 on Windows get affected by this vulnerability?
PuTTY before 0.75 on Windows can be affected by this vulnerability, which allows remote servers to cause a denial of service (Windows GUI hang) by repeatedly changing the PuTTY window title at high speed.
How can remote servers cause a denial of service on PuTTY before 0.75?
Remote servers can cause a denial of service on PuTTY before 0.75 by telling the PuTTY window to change its title repeatedly at high speed.
Are there any affected operating systems other than Windows for this vulnerability?
No, this vulnerability only affects PuTTY on Windows.
How can I mitigate the CVE-2021-33500 vulnerability in PuTTY before 0.75?
Update PuTTY to version 0.75 or later to mitigate the CVE-2021-33500 vulnerability.
Where can I find more information about the CVE-2021-33500 vulnerability?
You can find more information about the CVE-2021-33500 vulnerability at the following references: 1. [https://docs.ssh-mitm.at/puttydos.html](https://docs.ssh-mitm.at/puttydos.html) 2. [https://github.com/ssh-mitm/ssh-mitm-plugins/blob/main/ssh/putty_dos.py](https://github.com/ssh-mitm/ssh-mitm-plugins/blob/main/ssh/putty_dos.py) 3. [https://www.chiark.greenend.org.uk/~sgtatham/putty/changes.html](https://www.chiark.greenend.org.uk/~sgtatham/putty/changes.html)
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