Platform
curl
Component
curl
Fixed in
7.59.1
CVE-2018-16840 describes a heap use-after-free vulnerability discovered in cURL. This flaw arises during the cleanup process of an 'easy' handle within the Curl_close() function, where a struct is freed and then potentially accessed again. Successful exploitation could lead to denial of service or, in certain scenarios, arbitrary code execution. The vulnerability affects cURL versions 7.59.0 through 7.61.1, and a fix is available in version 7.62.0.
The heap use-after-free vulnerability in cURL allows an attacker to potentially trigger a crash or, more critically, execute arbitrary code. The specific impact depends on how cURL is integrated into the application using it. If cURL is used to fetch data from an untrusted source, a malicious server could craft a response that triggers the vulnerability during the cleanup process. This could lead to a denial of service, preventing the application from functioning correctly. In more complex scenarios, an attacker might be able to overwrite memory and gain control of the application's execution flow, leading to remote code execution. The severity is rated as medium due to the potential for code execution, although exploitation may require specific conditions and attacker interaction.
CVE-2018-16840 was publicly disclosed on October 31, 2018. While no active exploitation campaigns have been definitively linked to this vulnerability, the heap use-after-free nature makes it a potential target for exploitation. No public proof-of-concept (PoC) code has been widely released, but the vulnerability's nature suggests that a PoC could be developed. It is not currently listed on the CISA KEV catalog.
Exploit Status
CVSS Vector
The primary mitigation for CVE-2018-16840 is to upgrade to cURL version 7.62.0 or later, which contains the fix for this vulnerability. If upgrading is not immediately feasible, consider implementing temporary workarounds. One approach is to carefully validate the data received from external sources before passing it to cURL. This can help prevent malicious data from triggering the vulnerability. Additionally, consider using a Web Application Firewall (WAF) or proxy server to filter potentially malicious requests. While not a direct fix, these measures can reduce the attack surface. There are no specific Sigma or YARA rules readily available for this vulnerability, but monitoring memory access patterns related to cURL's easy handle cleanup could be a proactive detection strategy.
Actualice a una versión de cURL posterior a la 7.62.0 para mitigar la vulnerabilidad de uso de memoria después de la liberación. Verifique las fuentes oficiales de cURL para obtener instrucciones de actualización específicas para su sistema operativo y configuración.
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CVE-2018-16840 is a medium severity vulnerability in cURL versions 7.59.0 through 7.61.1, where a heap use-after-free occurs during easy handle cleanup, potentially leading to crashes or code execution.
You are affected if your system uses cURL versions 7.59.0 to 7.61.1. Check your cURL version and upgrade if necessary.
Upgrade to cURL version 7.62.0 or later to resolve this vulnerability. Consider temporary workarounds like data validation if immediate upgrade is not possible.
While no active campaigns have been definitively linked, the vulnerability's nature makes it a potential target. Monitor your systems for suspicious activity.
Refer to the cURL security advisories on the official cURL website for detailed information and updates: https://curl.se/security/.
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