A vulnerability in the xmlXPathCompOpEval() function of the XMLSoft libxml2 library could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on a targeted system.
The vulnerability exists in the xmlXPathCompOpEval() function, as defined in the path.c source code file of the affected software, and is due to improper parsing of invalid XPath expressions in the XPATH_OP_AND and XPATH_OP_OR cases. An attacker could exploit this vulnerability by sending a request that submits malicious input to an application that is using the affected library on a targeted system. A successful exploit could trigger a NULL pointer dereference condition, causing the affected application to crash and resulting in a DoS condition.
Proof-of-concept (PoC) code that demonstrates an exploit of this vulnerability is publicly available.
XMLSoft has confirmed the vulnerability and software updates are available.
To exploit this vulnerability, an attacker must send a request that submits malicious input to the targeted system, making exploitation more difficult in environments that restrict network access from untrusted sources.
Administrators are advised to contact the vendor regarding future updates and releases.
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.