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
Published · last modified .
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.
EPSS exploit prediction
EPSS: 0.016 (74.8th percentile), scored .
Low probability of exploitation in the next 30 days, but still tracked. 75th percentile — 74.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.016 · newest: 0.016 · change: 0.000
Affected products
- Lua
- Prosody
- Debian Linux — versions 9.0
- Fedoraproject Fedora — versions 32, 33, 34
Weakness classification (CWE)
Public proof-of-concept exploits
References
- blog.prosody.im/prosody-0.11.9-released/ (Release Notes, Vendor Advisory)
- www.openwall.com/lists/oss-security/2021/05/13/1 (mailing-list, Mailing List, Third Party Advisory)
- www.openwall.com/lists/oss-security/2021/05/14/2 (mailing-list, Mailing List, Third Party Advisory, Mitigation)
- www.debian.org/security/2021/dsa-4916 (vendor-advisory, Third Party Advisory)
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/… (vendor-advisory)
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/… (vendor-advisory)
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/… (vendor-advisory)
- security.gentoo.org/glsa/202105-15 (Third Party Advisory)
- lists.debian.org/debian-lts-announce/2021/06/msg00016.html (mailing-list, Mailing List, Third Party Advisory)
- lists.debian.org/debian-lts-announce/2021/06/msg00018.html (mailing-list, 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.