CVE-2019-12522
squid: lack of UID assignment in child process spawning could lead to privileges escalation
Severity
LowRed Hat Product Security
CVSS 3.1
Review impact separately from score.
Published · April 24, 2020
Updated · November 21, 2025
Description
A flaw was found in squid. When Squid is run as root, it spawns its child processes as a lesser user, by default the user nobody. This is done via the leave_suid call. leave_suid leaves the Saved UID as 0. This makes it trivial for an attacker who has compromised the child process to escalate their privileges back to root. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.
Statement
This issue is not a big problem on its own, as it requires another remote code execution vulnerability or that a local user has the privileges to modify the squid processes to be exploited. Thus, it is actually closer to a security enhancement than a vulnerability.
CVSS score applicability
The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.
Mitigation
No mitigation is specified in collected source.
CVSS / CWE
CVSS 3.1 · 4.5CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:L
CWE-266 · Incorrect Privilege Assignment