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Fencer Vulns
medium 6.3

CVE-2021-44964 json

Use after free in garbage collector and finalizer of lgc.c in Lua interpreter 5.4.0~5.4.3 allows attackers to perform Sandbox Escape via a…

published 2022-03-14 4 y ago modified 2026-09-08 2 mo ago also BIT-lua-2021-44964 , EUVD-2021-31762 , JLSEC-2026-558

cvss
6.3
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.0%
EPSS 1.0% chance of exploitation in 30 days, percentile 62%
public exploits
0
none known

Summary

Use after free in garbage collector and finalizer of lgc.c in Lua interpreter 5.4.0~5.4.3 allows attackers to perform Sandbox Escape via a crafted script file.

Patch / fix

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

debian advisories DEBIAN-CVE-2021-44964

  • 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

  • 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

  • ntopng Azure Linux 3.0 5.2.1-6
  • ntopng CBL-Mariner 2.0 5.2.1-3
  • memcached CBL-Mariner 2.0 1.6.22-2
  • lua CBL-Mariner 2.0 5.4.4-1

azure linux advisories AZL-40979AZL-60034AZL-60112AZL-9048

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

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-2021-44964 updated cvss 7.0

lua: use after free allows Sandbox Escape

  • Red Hat CodeReady Linux Builder (v. 9) lua 5.4.4-2.el9_1
    fixed: vendor fix “Ensure that the Lua interpreter runs only trusted scripts.” RHSA-2023:0957
  • Red Hat CodeReady Linux Builder EUS (v.9.0) lua 5.4.4-1.el9_0.1
    fixed: vendor fix “Ensure that the Lua interpreter runs only trusted scripts.” RHSA-2023:1211
  • Red Hat Enterprise Linux AppStream (v. 9) lua 5.4.4-2.el9_1
    fixed: vendor fix “Ensure that the Lua interpreter runs only trusted scripts.” RHSA-2023:0957
  • Red Hat Enterprise Linux AppStream EUS (v.9.0) lua 5.4.4-1.el9_0.1
    fixed: vendor fix “Ensure that the Lua interpreter runs only trusted scripts.” 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 “Ensure that the Lua interpreter runs only trusted scripts.” 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 “Ensure that the Lua interpreter runs only trusted scripts.” RHSA-2023:1211
  • Red Hat Enterprise Linux 6 lua Red Hat Enterprise Linux 7 lua 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

0.98% chance of exploitation in the next 30 days, higher than 62% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • lua-users.org http://lua-users.org/lists/lua-l/2021-11/msg00186.html referenced PoC, tagged "exploit" by a source, unverified
  • lua-users.org http://lua-users.org/lists/lua-l/2021-12/msg00007.html referenced PoC, tagged "exploit" by a source, unverified
  • github.com https://github.com/Lua-Project/lua-5.4.4-sandbox-escape-with-new-vulnerability referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 6.3 CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/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 6.3 CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:N/I:N/A:H

Affected packages

ecosystem package affected fixed in
bitnami lua
>=5.4.0, <5.4.4
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.