CVE-2021-3466
libmicrohttpd: Buffer overflow issue in URL parser in the post_process_urlencoded function
Severity
ImportantRed Hat Product Security
CVSS 3.1
Review impact separately from score.
Published · March 15, 2021
Updated · November 22, 2025
Description
A flaw was found in libmicrohttpd. A missing bounds check in the post_process_urlencoded function leads to a buffer overflow, allowing a remote attacker to write arbitrary data in an application that uses libmicrohttpd. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.
Statement
This issue do not affect the versions of libmicrohttpd as shipped with Red Hat Enterprise Linux 6, 7, and 8 as the vulnerable code was only introduced in later versions of the library.
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 · 8.1CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
CWE-120 · Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')