Vulnerability · Published May 12, 2026 · Assigned by GitHub_M
CVE-2026-44296Deskflow: TLS multiplexer DoS on failed `SSL_accept`
High 7.5
In plain English
A high-severity uncontrolled resource consumption in deskflow from deskflow. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 20% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
Deskflow is a keyboard and mouse sharing app. Prior to 1.26.0.167, a remote, unauthenticated denial of service (DoS) vulnerability affects Deskflow servers running with TLS enabled (the default). When any TCP peer connects to the listening port and its first bytes do not parse as a valid TLS ClientHello, SecureSocket::secureAccept enters its fatal-error branch and calls Arch::sleep(1) (a blocking 1-second sleep) on the multiplexer worker thread. That thread services every socket on the server, including established TLS clients delivering mouse motion, keyboard events, and clipboard updates. A single failed handshake therefore stalls input delivery to all connected screens for ~1 second, and a sustained drip of malformed connections (≥ 1/s) makes the server effectively unusable while the attack persists. This vulnerability is fixed in 1.26.0.167.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:13 | deskflow | no fix listed | DEBIAN-CVE-2026-44296 |
| Debian:14 | deskflow | 1.26.0+dfsg-3 | DEBIAN-CVE-2026-44296 |
| Ubuntu:25.10 | deskflow | no fix listed | UBUNTU-CVE-2026-44296 |
| Ubuntu:26.04:LTS | deskflow | no fix listed | UBUNTU-CVE-2026-44296 |
| Ubuntu:26.10 | deskflow | no fix listed | UBUNTU-CVE-2026-44296 |
Affected products (as reported)
Weakness: CWE-400, CWE-405 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H