How severe is CVE-2021-43519?

CVE-2021-43519 has a CVSS 3.x base score of 5.5, rated medium severity. It is exploitable over local access with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2021-43519 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (63rd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-43519?

CVE-2021-43519 primarily affects Lua. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-43519?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2021-43519 published?

CVE-2021-43519 was published on 2021-11-09 and last updated on 2026-06-17.

CVE-2021-43519

CVE-2021-43519 is a medium-severity vulnerability in Lua with a CVSS 3.x base score of 5.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-674.

Key facts

Severity: Medium (CVSS 3.x base score 5.5)
CVSS v2: 4.3
EPSS exploit prediction: 1% (63rd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-674
Affected product: Lua
Published: 2021-11-09
Last modified: 2026-06-17

Description

Stack overflow in lua_resume of ldo.c in Lua Interpreter 5.1.0~5.4.4 allows attackers to perform a Denial of Service via a crafted script file.

Frequently asked questions

What is CVE-2021-43519?: Stack overflow in lua_resume of ldo.c in Lua Interpreter 5.1.0~5.4.4 allows attackers to perform a Denial of Service via a crafted script file.
How severe is CVE-2021-43519?: CVE-2021-43519 has a CVSS 3.x base score of 5.5, rated medium severity. It is exploitable over local access with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2021-43519 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (63rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-43519?: CVE-2021-43519 primarily affects Lua. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-43519?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-43519 published?: CVE-2021-43519 was published on 2021-11-09 and last updated on 2026-06-17.

References

Affected products (2)

cpe:2.3:a:lua:lua:*:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:*

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