CVE-2023-49286: 
Squid vulnerability analysis and mitigation

CVE-2023-49286 affects Squid, a caching proxy for the Web supporting HTTP, HTTPS, and FTP. The vulnerability was discovered on December 4, 2023, and involves an Incorrect Check of Function Return Value bug that makes Squid vulnerable to a Denial of Service attack against its Helper process management (GitHub Advisory). The vulnerability affects all Squid versions prior to 6.5, including Squid-5.x up to 5.9 and Squid-6.x up to 6.4 (NVD).

The vulnerability stems from an incorrect check of the return value in the helper process management code. It has been assigned a CVSS v3.1 base score of 7.5 (HIGH) with the vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H, indicating that it can be exploited remotely with low attack complexity and requires no privileges or user interaction (GitHub Advisory, NVD).

When successfully exploited, this vulnerability allows attackers to perform a Denial of Service (DoS) attack against Squid's Helper process management. The attack is particularly effective when the Squid proxy is under load (GitHub Advisory).

The vulnerability has been fixed in Squid version 6.5. There are no known workarounds for this vulnerability, and users are advised to upgrade to the fixed version. For older versions, patches addressing this problem can be found in the Squid patch archives (GitHub Advisory).