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CVE-2018-8793: Rdesktop: Buffer overflow

CVE-2018-8793 is rated critical with a CVSS v3.1 base score of 9.8 and affects Rdesktop, along with 2 other products in NVD’s configuration data. Per its scoring, it can be exploited over the network, without authentication, without any user interaction. The scored impact on confidentiality, integrity and availability is the highest available.

Vulnerability description

rdesktop versions up to and including v1.8.3 contain a Heap-Based Buffer Overflow in function cssp_read_tsrequest() that results in a memory corruption and probably even a remote code execution.

Severity breakdown

CVSS v3.1 9.8: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Attack vector: Network. Exploitable remotely over the network, with no need for local or physical access.
Attack complexity: Low. No special conditions; the attack can be repeated reliably.
Privileges required: None. No account or prior access is needed.
User interaction: None. No action from any user is needed.
Scope: Unchanged. Impact stays within the vulnerable component.
Confidentiality impact: High. Total loss of confidentiality; sensitive data can be fully disclosed.
Integrity impact: High. Total loss of integrity; data or system state can be fully modified.
Availability impact: High. Total loss of availability; the component can be shut down.

Underlying weakness

CWE-122: Heap-based Buffer Overflow

The product writes past the end of a buffer that was allocated on the heap.

CWE-787: Out-of-bounds Write

The product writes data past the end, or before the beginning, of the intended buffer.

Affected products

Rdesktop: up to and including 1.8.3
Debian Linux: 8.0; 9.0
Opensuse Leap: 15.1