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CVE-2021-45985

25
FAUCET Score

CVE-2021-45985 describes a heap-based buffer over-read vulnerability in Lua 5.4.3, specifically triggered by an erroneous finalizer during a tail call. This vulnerability carries a CVSS score of 7.5 (HIGH), indicating a network-exploitable flaw with low attack complexity that can lead to high availability impact, though it does not affect confidentiality or integrity. There is currently no evidence of active exploitation, nor are there public exploit modules or significant community discussion surrounding this CVE.

Impacted Technologies

VendorProductVersion(s)CPE
>= 5.4.0, < 5.4.4CPE matchmatch criteria
cpe:2.3:a:lua:lua:*:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

7.5HIGH

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

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
HIGH
Exploitability Score
3.9
Impact Score
3.6
CvssVersion
3.1

Exploit Intelligence

EPSS Score
1.42%
Probability of exploitation in next 30 days
EPSS Percentile
70.0%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0142 is in the 51st percentile among its peer group of 51,551 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.1 Mastodon, and 0.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (26)

github_advisorypatch availablevia nvd_reference
View patch
microsoftpatch availablevia msrc
Product: Windows Server 2022Fixed in: 10.0.20348.2762
View patch
microsoftpatch availablevia msrc
Product: Windows Server 2022 (Server Core installation)Fixed in: 10.0.20348.2762
View patch
microsoftpatch availablevia msrc
Product: Windows 10 Version 21H2 for 32-bit SystemsFixed in: 10.0.19044.5011
View patch
microsoftpatch availablevia msrc
Product: Windows 10 Version 21H2 for ARM64-based SystemsFixed in: 10.0.19044.5011
View patch
microsoftpatch availablevia msrc
Product: Windows 10 Version 21H2 for x64-based SystemsFixed in: 10.0.19044.5011
View patch
microsoftpatch availablevia msrc
Product: Windows 11 Version 22H2 for ARM64-based SystemsFixed in: 10.0.22621.4317
View patch
microsoftpatch availablevia msrc
Product: Windows 11 Version 22H2 for x64-based SystemsFixed in: 10.0.22621.4317
View patch
microsoftpatch availablevia msrc
Product: Windows 10 Version 22H2 for x64-based SystemsFixed in: 10.0.19045.5011
View patch
microsoftpatch availablevia msrc
Product: Windows 10 Version 22H2 for ARM64-based SystemsFixed in: 10.0.19045.5011
View patch
microsoftpatch availablevia msrc
Product: Windows 10 Version 22H2 for 32-bit SystemsFixed in: 10.0.19045.5011
View patch
microsoftpatch availablevia msrc
Product: Windows 11 Version 23H2 for ARM64-based SystemsFixed in: 10.0.22631.4317
View patch
microsoftpatch availablevia msrc
Product: Windows 11 Version 23H2 for x64-based SystemsFixed in: 10.0.22631.4317
View patch
microsoftpatch availablevia msrc
Product: Windows Server 2022, 23H2 Edition (Server Core installation)Fixed in: 10.0.25398.1189
View patch
microsoftpatch availablevia msrc
Product: Windows 11 Version 24H2 for ARM64-based SystemsFixed in: 10.0.26100.2894
View patch
microsoftpatch availablevia msrc
Product: Windows 11 Version 24H2 for x64-based SystemsFixed in: 10.0.26100.2894
View patch
microsoftpatch availablevia msrc
Product: Windows Server 2025Fixed in: 10.0.26100.2894
View patch
microsoftpatch availablevia msrc
Product: Windows Server 2025 (Server Core installation)Fixed in: 10.0.26100.2894
View patch
microsoftpatch availablevia msrc
Product: CBL Mariner 2.0 x64Fixed in: 5.4.3-5
microsoftpatch availablevia msrc
Product: CBL Mariner 2.0 x64Fixed in: 1.6.13-3
microsoftpatch availablevia msrc
Product: CBL Mariner 2.0 x64Fixed in: 5.2.1-2
microsoftpatch availablevia msrc
Product: Azure Linux 3.0 x64Fixed in: 5.2.1-2
microsoftpatch availablevia msrc
Product: Azure Linux 3.0 ARMFixed in: 5.2.1-2
microsoftpatch availablevia msrc
Product: CBL Mariner 2.0 ARMFixed in: 5.4.3-5
microsoftpatch availablevia msrc
Product: CBL Mariner 2.0 ARMFixed in: 1.6.13-3
microsoftpatch availablevia msrc
Product: CBL Mariner 2.0 ARMFixed in: 5.2.1-2

Vendor Advisories (2)

microsoft2023-Apr/CVE-2021-45985Important

Mitre: CVE-2021-45985 Erroneous finalizer call in Lua leads to a heap-based buffer over-read

Apr 11, 2023
redhatCVE-2021-45985Moderate

lua: heap-based buffer over-read

Apr 10, 2023

References

lua-users.org / lists/lua-l/2021-12/msg00019.html
ExploitMailing ListVendor Advisory
github.com / lua/lua/commit/cf613cdc6fa367257fc61c256f63d917350858b5
Patch
lua.org / bugs.html
Vendor Advisory