CVE-2021-33500

low

Published — · Modified —

CVSS v3

—

CVSS v2

—

VIR risk

2.5

Description

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.

Predictions

Exploit likelihood

20%

Patch ETA

—

Heuristic predictions, AS-IS, for prioritization only.

Mitigations

vendor Authored 2026-05-27

Vendor advisory: debian — https://security-tracker.debian.org/tracker/CVE-2021-33500

OS impact

OS	Version	Status	Fixed in
arch		fixed	`0.75-1`
debian	bookworm	fixed	`0`
debian	bullseye	fixed	`0`
debian	forky	fixed	`0`
debian	sid	fixed	`0`
debian	trixie	fixed	`0`

References

https://security-tracker.debian.org/tracker/CVE-2021-33500

Verify integrity in audit chain (admin only). AS-IS.