CVE-2021-3466
9.8
CRITICAL · CVSS 3.1 · EPSS 8.7% (pctl 95)
In your normal cycle
Critical by CVSS (9.8), but no sign of active exploitation.
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.
Scoring
| CVSS | 9.8 (CRITICAL, v3.1) |
|---|---|
| Vector | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
| EPSS | 8.74% — more likely to be exploited than 95% of all CVEs |
| Weakness | CWE-120 |
| On CISA KEV | no |
| Public exploit | none known |
| Published | 2021-03-25 |
| Last modified | 2026-06-17 |
Affected (3)
| Vendor | Product |
|---|---|
| fedoraproject | fedora |
| gnu | libmicrohttpd |
| redhat | enterprise linux |
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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