CVE-2026-67303

FreeRDP before 3.29.0 Denial of Service via serial DeviceControl

5.3 MediumFix available

FreeRDP before 3.29.0 contains a reachable assertion (WINPR_ASSERT(OutputBufferLength == BytesReturned)) in serial_process_irp_device_control() in channels/serial/client/serial_main.c. When serial device redirection is enabled and a server-controlled IRP_MJ_DEVICE_CONTROL request specifies an unsupported IOCTL with a non-zero OutputBufferLength, CommDeviceIoControl() can fail with BytesReturned = 0, causing the mismatch to trigger the assertion and abort the client process (denial of service).

Attack profile

How easy it is to exploit

Attack vector: Network
Complexity: Low
Privileges needed: None
User interaction: Passive

What an attacker can affect

Confidentiality: None
Integrity: None
Availability: Low

Exploit likelihood

0.42%Up 0.2 points since Aug 2, 2026

What each source reports

CVE List Score used 5.3

FreeRDP before 3.29.0 Denial of Service via serial DeviceControl

Record: CVE-2026-67303
CVSS 4.0: 5.3 MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
CVSS 3.1: 4.3 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L
Weakness: CWE-617
Updated: 2026-11-02

EUVDEUVD-2026-51818 5.3

Record: EUVD-2026-51818
CVSS 4.0: 5.3 MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
Updated: 2026-11-02

GitHub AdvisoriesGHSA-4wq4-c34j-gg99 5.3

FreeRDP before 3.29.0 contains a reachable assertion (WINPR_ASSERT(OutputBufferLength ==...

Record: GHSA-4wq4-c34j-gg99
CVSS 4.0: 5.3 MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CVSS 3.1: 4.3 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L
Weakness: CWE-617
Updated: 2026-11-02

NVD 5.3

Record: CVE-2026-67303
CVSS 4.0: 5.3 MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CVSS 3.1: 4.3 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L
Weakness: CWE-617
Updated: 2026-11-02

OSV 5.3

FreeRDP before 3.29.0 Denial of Service via serial DeviceControl

Record: CVE-2026-67303
CVSS 4.0: 5.3 MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
Weakness: CWE-617
Updated: 2026-11-02

OSVDEBIAN-CVE-2026-67303 5.3

Record: DEBIAN-CVE-2026-67303
CVSS 4.0: 5.3 MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Updated: 2026-11-02

OSVUBUNTU-CVE-2026-67303 5.3

Record: UBUNTU-CVE-2026-67303
CVSS 4.0: 5.3 MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
CVSS 3.1: 4.3 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L
Updated: 2026-11-02

Affected products

freerdp

Affected packages

Affected packages
Package	Affected	Fixed
`freerdp2` Debian:12	All versions, plus listed versions 2.10.0+dfsg1-12.10.0+dfsg1-1.12.11.2+dfsg1-12.11.2+dfsg1-1.1~exp12.11.2+dfsg1-1.1~exp2 Show 8 moreShow less 2.11.5+dfsg1-12.11.7+dfsg1-12.11.7+dfsg1-22.11.7+dfsg1-32.11.7+dfsg1-42.11.7+dfsg1-52.11.7+dfsg1-62.11.7+dfsg1-6~deb12u1	None known
`freerdp3` Debian:13	All versions, plus listed versions 3.15.0+dfsg-2.13.15.0+dfsg-2.1+deb13u13.15.0+dfsg-2.1+deb13u23.15.0+dfsg-2.1+deb13u33.16.0+dfsg-1 Show 44 moreShow less 3.16.0+dfsg-23.17.0+dfsg-13.17.1+dfsg-13.17.1+dfsg-23.17.2+dfsg-13.17.2+dfsg-23.17.2+dfsg-33.18.0+dfsg-13.19.0+dfsg-13.19.1+dfsg-13.20.0+dfsg-13.20.2+dfsg-13.21.0+dfsg-13.22.0+dfsg-13.22.0+dfsg-1~bpo13+03.22.0+dfsg-1~bpo13+13.22.0+dfsg-33.23.0+dfsg-13.23.0+dfsg-1~bpo13+13.24.0+dfsg-13.24.0+dfsg-23.24.1+dfsg-13.24.2+dfsg-13.24.2+dfsg-1~bpo13+13.25.0+dfsg-13.25.0+dfsg-23.25.0+dfsg-33.25.0+dfsg-43.25.0+dfsg-53.26.0+dfsg-13.26.0+dfsg-1~bpo13+13.27.0+dfsg-13.27.1+dfsg-13.28.0+dfsg-13.28.0+dfsg-23.29.0+dfsg-13.30.0+dfsg-13.30.0+dfsg-1~bpo13+13.31.0+dfsg-13.31.1+dfsg-13.31.1+dfsg-1~bpo13+13.32.0+dfsg-13.32.1+dfsg-13.32.1+dfsg-1~bpo13+1	None known
`freerdp3` Debian:14	before 3.29.0+dfsg-1, plus listed versions 3.15.0+dfsg-2.13.16.0+dfsg-13.16.0+dfsg-23.17.0+dfsg-13.17.1+dfsg-1 Show 32 moreShow less 3.17.1+dfsg-23.17.2+dfsg-13.17.2+dfsg-23.17.2+dfsg-33.18.0+dfsg-13.19.0+dfsg-13.19.1+dfsg-13.20.0+dfsg-13.20.2+dfsg-13.21.0+dfsg-13.22.0+dfsg-13.22.0+dfsg-1~bpo13+03.22.0+dfsg-1~bpo13+13.22.0+dfsg-33.23.0+dfsg-13.23.0+dfsg-1~bpo13+13.24.0+dfsg-13.24.0+dfsg-23.24.1+dfsg-13.24.2+dfsg-13.24.2+dfsg-1~bpo13+13.25.0+dfsg-13.25.0+dfsg-23.25.0+dfsg-33.25.0+dfsg-43.25.0+dfsg-53.26.0+dfsg-13.26.0+dfsg-1~bpo13+13.27.0+dfsg-13.27.1+dfsg-13.28.0+dfsg-13.28.0+dfsg-2	3.29.0+dfsg-1
`freerdp` Ubuntu:16.04:LTS	All versions, plus listed versions 1.1.0~git20140921.1.440916e+dfsg1-5ubuntu11.1.0~git20140921.1.440916e+dfsg1-5ubuntu1.21.1.0~git20140921.1.440916e+dfsg1-5ubuntu1.31.1.0~git20140921.1.440916e+dfsg1-5ubuntu1.4	None known
`freerdp2` Ubuntu:Pro:18.04:LTS	All versions, plus listed versions 2.0.0~git20170725.1.1648deb+dfsg1-12.0.0~git20170725.1.1648deb+dfsg1-52.0.0~git20170725.1.1648deb+dfsg1-5ubuntu12.0.0~git20170725.1.1648deb+dfsg1-5ubuntu22.0.0~git20170725.1.1648deb+dfsg1-6 Show 14 moreShow less 2.0.0~git20170725.1.1648deb+dfsg1-6build12.0.0~git20170725.1.1648deb+dfsg1-72.0.0~git20170725.1.1648deb+dfsg1-7ubuntu0.12.1.1+dfsg1-0ubuntu0.18.04.12.2.0+dfsg1-0ubuntu0.18.04.12.2.0+dfsg1-0ubuntu0.18.04.22.2.0+dfsg1-0ubuntu0.18.04.32.2.0+dfsg1-0ubuntu0.18.04.42.2.0+dfsg1-0ubuntu0.18.04.4+esm12.2.0+dfsg1-0ubuntu0.18.04.4+esm22.2.0+dfsg1-0ubuntu0.18.04.4+esm32.2.0+dfsg1-0ubuntu0.18.04.4+esm42.2.0+dfsg1-0ubuntu0.18.04.4+esm52.2.0+dfsg1-0ubuntu0.18.04.4+esm6	None known
`freerdp` Ubuntu:18.04:LTS	All versions, plus listed versions 1.1.0~git20140921.1.440916e+dfsg1-15ubuntu11.1.0~git20140921.1.440916e+dfsg1-15ubuntu1.18.04.11.1.0~git20140921.1.440916e+dfsg1-15ubuntu1.18.04.2	None known
`freerdp2` Ubuntu:Pro:20.04:LTS	All versions, plus listed versions 2.0.0~git20190204.1.2693389a+dfsg1-12.0.0~git20190204.1.2693389a+dfsg1-22.0.0~git20190204.1.2693389a+dfsg1-2build12.0.0~git20190204.1.2693389a+dfsg1-2build22.1.1+dfsg1-0ubuntu0.20.04.1 Show 12 moreShow less 2.2.0+dfsg1-0ubuntu0.20.04.12.2.0+dfsg1-0ubuntu0.20.04.22.2.0+dfsg1-0ubuntu0.20.04.32.2.0+dfsg1-0ubuntu0.20.04.42.2.0+dfsg1-0ubuntu0.20.04.52.2.0+dfsg1-0ubuntu0.20.04.62.6.1+dfsg1-0ubuntu0.20.04.12.6.1+dfsg1-0ubuntu0.20.04.22.6.1+dfsg1-0ubuntu0.20.04.2+esm12.6.1+dfsg1-0ubuntu0.20.04.2+esm22.6.1+dfsg1-0ubuntu0.20.04.2+esm32.6.1+dfsg1-0ubuntu0.20.04.2+esm4	None known
`freerdp2` Ubuntu:22.04:LTS	All versions, plus listed versions 2.3.0+dfsg1-2build12.3.0+dfsg1-2ubuntu12.3.0+dfsg1-2ubuntu22.4.1+dfsg1-12.4.1+dfsg1-1ubuntu1 Show 18 moreShow less 2.4.1+dfsg1-1ubuntu22.5.0+dfsg1-12.6.0+dfsg1-12.6.1+dfsg1-12.6.1+dfsg1-32.6.1+dfsg1-3ubuntu12.6.1+dfsg1-3ubuntu22.6.1+dfsg1-3ubuntu2.12.6.1+dfsg1-3ubuntu2.22.6.1+dfsg1-3ubuntu2.32.6.1+dfsg1-3ubuntu2.42.6.1+dfsg1-3ubuntu2.52.6.1+dfsg1-3ubuntu2.62.6.1+dfsg1-3ubuntu2.72.6.1+dfsg1-3ubuntu2.82.6.1+dfsg1-3ubuntu2.92.6.1+dfsg1-3ubuntu2.102.6.1+dfsg1-3ubuntu2.11	None known
`freerdp3` Ubuntu:24.04:LTS	before 3.30.0+dfsg-0ubuntu0.24.04.1, plus listed versions 3.4.0+dfsg1-0ubuntu23.4.0+dfsg1-0ubuntu33.4.0+dfsg1-0ubuntu43.5.0+dfsg1-0ubuntu13.5.1+dfsg1-0ubuntu1 Show 5 moreShow less 3.5.1+dfsg1-0ubuntu1.13.5.1+dfsg1-0ubuntu1.23.5.1+dfsg1-0ubuntu1.43.5.1+dfsg1-0ubuntu1.53.5.1+dfsg1-0ubuntu1.6	3.30.0+dfsg-0ubuntu0.24.04.1
`freerdp2` Ubuntu:Pro:24.04:LTS	All versions, plus listed versions 2.10.0+dfsg1-1.1ubuntu12.11.2+dfsg1-12.11.2+dfsg1-1build12.11.2+dfsg1-1build32.11.5+dfsg1-1build1 Show 7 moreShow less 2.11.5+dfsg1-1build22.11.5+dfsg1-1ubuntu0.1~esm12.11.5+dfsg1-1ubuntu0.1~esm22.11.5+dfsg1-1ubuntu0.1~esm32.11.5+dfsg1-1ubuntu0.1~esm42.11.5+dfsg1-1ubuntu0.1~esm52.11.5+dfsg1-1ubuntu0.1~esm6	None known
`freerdp3` Ubuntu:26.04:LTS	before 3.30.0+dfsg-0ubuntu0.26.04.1, plus listed versions 3.16.0+dfsg-23.18.0+dfsg-1ubuntu13.19.0+dfsg-13.19.1+dfsg-13.20.0+dfsg-1 Show 6 moreShow less 3.20.2+dfsg-13.21.0+dfsg-13.22.0+dfsg-13.24.1+dfsg-1ubuntu13.24.2+dfsg-1ubuntu13.24.2+dfsg-1ubuntu1.1	3.30.0+dfsg-0ubuntu0.26.04.1

History

History
Recorded	Changed	Sources
Nov 2, 2026	first indexed	CVE List, EUVD, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2026-67303 is a medium vulnerability (CVSS 5.3) in Freerdp, published August 1, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.42%, the 36th percentile. Fixed in freerdp3 3.29.0+dfsg-1.

References

Show 4 moreShow less