CVE-2021-32921

Name: CVE-2021-32921
Creator: NVD / NIST
Published: 2021-05-13T16:15:08.407+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 5.9/10EPSS 1.60%

Last modified Jun 17, 2026

CVE-2021-32921 is a medium-severity vulnerability rated 5.9/10 on the CVSS scale. An issue was discovered in Prosody before 0.11.9. It does not use a constant-time algorithm for comparing certain secret strings when running under Lua 5.2 or later. EPSS estimates a 1.60% chance of exploitation in the next 30 days.

Description

An issue was discovered in Prosody before 0.11.9. It does not use a constant-time algorithm for comparing certain secret strings when running under Lua 5.2 or later. This can potentially be used in a timing attack to reveal the contents of secret strings to an attacker.

Metrics

CVSS 3.1

5.9/10

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

EPSS Probability

1.60%

72.7th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-362

Affected Software

Vendor	Product	Versions
Prosody	Prosody	< 0.11.9
Fedoraproject	Fedora	32
Fedoraproject	Fedora	33
Fedoraproject	Fedora	34
Debian	Debian Linux	9.0

References

http://www.openwall.com/lists/oss-security/2021/05/13/1Mailing List, Third Party Advisory
http://www.openwall.com/lists/oss-security/2021/05/14/2Mailing List, Mitigation, Third Party Advisory
https://blog.prosody.im/prosody-0.11.9-released/Release Notes, Vendor Advisory
https://lists.debian.org/debian-lts-announce/2021/06/msg00016.htmlMailing List, Third Party Advisory
https://lists.debian.org/debian-lts-announce/2021/06/msg00018.htmlThird Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/6MFFBZWXKPZEVZNQSVJNCUE7WRF3T7DG/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/GUN63AHEWB2WRROJHU3BVJRWLONCT2B7/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/LWJ2DG2DFJOEFEWOUN26IMYYWGSA2ZEE/
https://security.gentoo.org/glsa/202105-15Third Party Advisory
https://www.debian.org/security/2021/dsa-4916Third Party Advisory
http://www.openwall.com/lists/oss-security/2021/05/13/1Mailing List, Third Party Advisory
http://www.openwall.com/lists/oss-security/2021/05/14/2Mailing List, Mitigation, Third Party Advisory
https://blog.prosody.im/prosody-0.11.9-released/Release Notes, Vendor Advisory
https://lists.debian.org/debian-lts-announce/2021/06/msg00016.htmlMailing List, Third Party Advisory
https://lists.debian.org/debian-lts-announce/2021/06/msg00018.htmlThird Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/6MFFBZWXKPZEVZNQSVJNCUE7WRF3T7DG/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/GUN63AHEWB2WRROJHU3BVJRWLONCT2B7/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/LWJ2DG2DFJOEFEWOUN26IMYYWGSA2ZEE/
https://security.gentoo.org/glsa/202105-15Third Party Advisory
https://www.debian.org/security/2021/dsa-4916Third Party Advisory

Timeline

Published: May 13, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-32921?

How severe is CVE-2021-32921?

CVE-2021-32921 has a CVSS score of 5.9/10 (MEDIUM severity). The EPSS model estimates a 1.60% probability of exploitation in the next 30 days.

How do I fix CVE-2021-32921?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-32921?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST