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Fencer Vulns
medium 5.5

CVE-2021-43519 json

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 f…

published 2021-11-09 4 y ago modified 2026-09-08 2 mo ago also BIT-lua-2021-43519 , EUVD-2021-30448 , JLSEC-2026-556

cvss
5.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.2%
EPSS 1.2% chance of exploitation in 30 days, percentile 69%
public exploits
0
none known

Summary

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.

Patch / fix

  • bitnami lua 5.3.5, 5.4.4
  • julia Lua_jll 5.4.4+0
  • lua lua 5.3.5, 5.4.4
  • lua5.4 Debian 14, Debian 13, Debian 12 5.4.4-1

debian advisories DEBIAN-CVE-2021-43519

  • lua RHEL 9 5.4.4-2.el9_1
  • lua-libs RHEL 9 5.4.4-2.el9_1
  • lua RHEL 9.0 EUS 5.4.4-1.el9_0.1
  • lua-libs RHEL 9.0 EUS 5.4.4-1.el9_0.1

red hat advisories RHSA-2023:1211RHSA-2023:0957

  • lua55 openSUSE Tumbleweed 5.5.0~beta1-1.1

opensuse advisories openSUSE-SU-2025:15401-1

  • lua AlmaLinux 9 5.4.4-2.el9_1
  • lua-libs AlmaLinux 9 5.4.4-2.el9_1

almalinux advisories ALSA-2023:0957

  • lua Rocky Linux 9 5.4.4-2.el9_1

rocky linux advisories RLSA-2023:0957

  • ceph Azure Linux 3.0 18.2.2-3
  • ntopng Azure Linux 3.0 5.2.1-5
  • lua Azure Linux 3.0 5.4.4-1
  • memcached Azure Linux 3.0 1.6.27-2
  • lua CBL-Mariner 2.0 5.4.3-1

azure linux advisories AZL-41261AZL-41445AZL-41574AZL-41866AZL-6672

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

  • lua Arch Linux 5.4.4-1

arch linux advisories AVG-2535

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2021-43519 updated cvss 5.5

lua: stack overflow in lua_resume of ldo.c allows a DoS via a crafted script file

  • Red Hat Enterprise Linux 6 lua Red Hat Enterprise Linux 7 lua
    affected: no fix planned “Out of support scope”
  • Red Hat CodeReady Linux Builder (v. 9) lua 5.4.4-2.el9_1
    fixed: vendor fix RHSA-2023:0957
  • Red Hat CodeReady Linux Builder EUS (v.9.0) lua 5.4.4-1.el9_0.1
    fixed: vendor fix RHSA-2023:1211
  • Red Hat Enterprise Linux AppStream (v. 9) lua 5.4.4-2.el9_1
    fixed: vendor fix RHSA-2023:0957
  • Red Hat Enterprise Linux AppStream EUS (v.9.0) lua 5.4.4-1.el9_0.1
    fixed: vendor fix RHSA-2023:1211
  • Red Hat Enterprise Linux BaseOS (v. 9) lua 5.4.4-2.el9_1, lua-libs 5.4.4-2.el9_1
    fixed: vendor fix RHSA-2023:0957
  • Red Hat Enterprise Linux BaseOS EUS (v.9.0) lua 5.4.4-1.el9_0.1, lua-libs 5.4.4-1.el9_0.1
    fixed: vendor fix RHSA-2023:1211
  • Red Hat Enterprise Linux 8 lua, lua-libs Red Hat JBoss Core Services lua
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

1.23% chance of exploitation in the next 30 days, higher than 69% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • lua-users.org http://lua-users.org/lists/lua-l/2021-10/msg00123.html referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
NVD 2.0 4.3 AV:N/AC:M/Au:N/C:N/I:N/A:P
OSV 3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

Affected packages

ecosystem package affected fixed in
bitnami lua
>=5.1.0, <5.3.5
>=5.4.0, <5.4.4
5.3.5
5.4.4
julia Lua_jll
>=5.4.3+0, <5.4.4+0
5.4.4+0

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.