A vulnerability in X.Org libX11 could allow an unauthenticated, remote attacker to execute arbitrary code on a targeted system.
The vulnerability exists because the affected software client running on the target system improperly handles responses from end-user-controlled server instances. An attacker could exploit this vulnerability by sending a response that submits malicious input to the affected software. A successful exploit could trigger an off-by-one memory write condition in the XGetFontPath(), XListExtensions(), and XListFonts() functions of the affected software client, which the attacker could use to execute arbitrary code on the affected system running the client.
X.Org confirmed the vulnerability and released software updates.
To exploit this vulnerability, the attacker must send a malicious request to the targeted system, making exploitation more difficult in environments that restrict network access from untrusted sources.
Administrators are advised to apply the appropriate updates.
Administrators are advised to allow only trusted users to have network access.
Administrators are advised to run both firewall and antivirus applications to minimize the potential of inbound and outbound threats.
Administrators may consider using IP-based access control lists (ACLs) to allow only trusted systems to access the affected systems.
Administrators can help protect affected systems from external attacks by using a solid firewall strategy.
Administrators are advised to monitor affected systems.
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Cisco Multivendor Vulnerability Alerts respond to vulnerabilities identified in third-party vendors' products. These alerts contain information compiled from diverse sources and provide comprehensive technical descriptions, objective analytical assessments, workarounds and practical safeguards, and links to vendor advisories and patches.