Out-of-bounds Read in Deskflow

CVE-2026-63409

Deskflow is a keyboard and mouse sharing app. From 1.17.0 until continuous build 1.26.0.296, a malicious Deskflow server can send an odd-length DSOP vector to ServerProxy::setOptions() in src/lib/client/ServerProxy.cpp, causing the missing value after the final option key to be read beyond the vector during the PacketStreamFilter::filterEvent to ServerProxy::handleData() to ServerProxy::parseHandshakeMessage() call chain and crash the connected client. This issue is fixed in continuous build 1.26.0.296.

Vulnerability class: Buffer Overflow

Published · last modified .

CVSS v3 metric

CVSS v3 base score 8.2 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H.

EPSS exploit prediction

EPSS: 0.005 (37.0th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 37th percentile — 37.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-63409: held from 0.003 to 0.005.

EPSS over last 30 days · oldest: 0.003 · newest: 0.005 · change: +0.002

Affected products

  • Deskflow — versions >= 1.17.0, < 1.26.0.296

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-63409?
CVE-2026-63409 is a high-severity vulnerability in Deskflow, classified under Out-of-bounds Read. CVSS score: 8.2/10. Published 2026-08-17.
How severe is CVE-2026-63409?
High severity. CVSS v3 base score is 8.2 out of 10.