CVE-2021-3466
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.
Key facts
- CVSS score
- 9.8 (v3.1)
- Severity
- CRITICAL
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H- Weakness (CWE)
- CWE-120
- EPSS score
- 8.7% (95th percentile)
- In CISA KEV
- No
- In EU EUVD
- Yes (EUVD-2021-26788)
- Published
- March 25, 2021
- NVD last modified
- June 17, 2026
- Status
- Modified
EU Vulnerability Database (EUVD)
This vulnerability is also tracked by ENISA as EUVD-2021-26788 in the EU Vulnerability Database. Last updated in EUVD on August 3, 2024.
View on the EU Vulnerability DatabaseAffected products
- fedoraproject / fedora
- fedoraproject / fedora
- fedoraproject / fedora
- gnu / libmicrohttpd
- redhat / enterprise linux
- redhat / enterprise linux
- redhat / enterprise linux
Certified products that may be affected
23 FIPS 140 or Common Criteria certified products, from automated matching by sec-certs.org.
- Red Hat Enterprise Linux 8 NSS Cryptographic Module - Red Hat, Inc. - FIPS 140 5513 - active
- Red Hat Enterprise Linux 8 Kernel Cryptographic API - Red Hat, LLC - FIPS 140 5461 - active
- Red Hat Enterprise Linux 8 Kernel Cryptographic API - Red Hat, Inc. - FIPS 140 5089 - active
- Red Hat Enterprise Linux 8 OpenSSL Cryptographic Module - Red Hat®, Inc. - FIPS 140 4642 - historical
- Red Hat Enterprise Linux 8 NSS Cryptographic Module - Red Hat®, Inc. - FIPS 140 4458 - historical
See all 23 in the Security Certifications Explorer.
References
- https://bugzilla.redhat.com/show_bug.cgi?id=1939127(Issue Tracking, Patch, Third Party Advisory)
- 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
Last updated September 17, 2026 · Source: NVD, CISA KEV, FIRST.org EPSS
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