CVE-2023-27536: Medium severity IBM IBM® Engineering Requirements Management DOORS vulnerability
An authentication bypass vulnerability exists libcurl <8.0.0 in the connection reuse feature which can reuse previously established connections with incorrect user permissions due to a failure to check for changes in the CURLOPTGSSAPIDELEGATION option. This vulnerability affects krb5/kerberos/negotiate/GSSAPI transfers and could potentially result in unauthorized access to sensitive information. The safest option is to not reuse connections if the CURLOPTGSSAPIDELEGATION option has been changed.
Other sources
cURL libcurl could allow a remote attacker to bypass security restrictions, caused by a GSS delegation too eager connection re-use flaw. By sending a specially crafted request, an attacker could exploit this vulnerability to reuse a previously created connection even when the GSS delegation.
— IBM
libcurl would reuse a previously created connection even when the GSS delegation (CURLOPTGSSAPIDELEGATION) option had been changed that could have changed the user's permissions in a second transfer. libcurl keeps previously used connections in a connection pool for subsequent transfers to reuse if one of them matches the setup. However, this GSS delegation setting was left out from the configuration match checks, making them match too easily, affecting krb5/kerberos/negotiate/GSSAPI transfers.
— Red Hat
Affected Software
Event History
Frequently Asked Questions
What is CVE-2023-27536?
CVE-2023-27536 is an authentication bypass vulnerability in libcurl that allows the reuse of previously established connections with incorrect user permissions.
Which software is affected by CVE-2023-27536?
CVE-2023-27536 affects libcurl versions prior to 8.0.0 and various operating systems and applications that use libcurl, such as Red Hat, Fedora, Debian, and Apple macOS.
What is the severity of CVE-2023-27536?
The severity of CVE-2023-27536 is medium, with a CVSSv3 score of 5.9.
How can I fix CVE-2023-27536?
To fix CVE-2023-27536, you need to update libcurl to version 8.0.0 or higher, or apply the relevant security patches provided by your operating system or software vendor.
Where can I find more information about CVE-2023-27536?
You can find more information about CVE-2023-27536 on the official Red Hat Bugzilla page and the Red Hat Security Advisory.