Vulnerability in Lua
CVE-2021-32921
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.
Vulnerability class: Race Condition
EPSS: 0.016 (73.3th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 5.9 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N.
Affected products
- Lua
- Prosody
- Debian Debian_linux — versions 9.0
- Fedoraproject Fedora — versions 32, 33, 34
- N/a — versions n/a
Weakness classification (CWE)
Public proof-of-concept exploits
References
- cve@mitre.org (x_refsource_MISC, Release Notes, Vendor Advisory)
- cve@mitre.org (mailing-list, x_refsource_MLIST, Mailing List, Third Party Advisory)
- cve@mitre.org (mailing-list, x_refsource_MLIST, Mailing List, Third Party Advisory, Mitigation)
- cve@mitre.org (vendor-advisory, Third Party Advisory, x_refsource_DEBIAN)
- cve@mitre.org (x_refsource_FEDORA, vendor-advisory)
- cve@mitre.org (x_refsource_FEDORA, vendor-advisory)
- cve@mitre.org (x_refsource_FEDORA, vendor-advisory)
- cve@mitre.org (Third Party Advisory, x_refsource_MISC)
- cve@mitre.org (mailing-list, x_refsource_MLIST, Mailing List, Third Party Advisory)
- cve@mitre.org (mailing-list, x_refsource_MLIST, Third Party Advisory)
Frequently asked questions
- What is CVE-2021-32921?
- CVE-2021-32921 is a medium-severity vulnerability in Lua, classified under Concurrent Execution using Shared Resource with Improper Synchronization (Race Condition). CVSS score: 5.9/10. Published 2021-05-13.
- How severe is CVE-2021-32921?
- Medium severity. CVSS v3 base score is 5.9 out of 10.
- Is CVE-2021-32921 known to be exploited?
- 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.