CVE-2021-3466

Severity: critical (CVSS 9.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 8.7% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2021-03-25 · updated 2026-06-17
Weakness: CWE-120

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. Only version 0.9.70 is vulnerable.

Affected products

Fedoraproject Fedora: 32, 33, 34
GNU Libmicrohttpd: 0.9.70
Red Hat Enterprise Linux: 6.0, 7.0, 8.0

References

https://bugzilla.redhat.com/show_bug.cgi?id=1939127
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/4334XJNDJPYQNFE6S3S2KUJJ7TMHYCWL/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/75HDMREKITMGPGE62NP7KE62ZJVLETXN/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/K5NEPVGP3L2CZHLZ4UB44PEILHKPDBOG/
https://security.gentoo.org/glsa/202311-08
https://bugzilla.redhat.com/show_bug.cgi?id=1939127
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/4334XJNDJPYQNFE6S3S2KUJJ7TMHYCWL/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/75HDMREKITMGPGE62NP7KE62ZJVLETXN/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/K5NEPVGP3L2CZHLZ4UB44PEILHKPDBOG/
https://security.gentoo.org/glsa/202311-08

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