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Fencer Vulns
medium 5.3

CVE-2020-24370 json

ldebug.c in Lua 5.4.0 allows a negation overflow and segmentation fault in getlocal and setlocal, as demonstrated by getlocal(3,2^31).

published 2020-08-17 6 y ago modified 2026-09-08 2 mo ago also BIT-lua-2020-24370 , EUVD-2020-17102 , JLSEC-2026-555

cvss
5.3
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
3.8%
EPSS 3.8% chance of exploitation in 30 days, percentile 90%
public exploits
0
none known

Summary

ldebug.c in Lua 5.4.0 allows a negation overflow and segmentation fault in getlocal and setlocal, as demonstrated by getlocal(3,2^31).

Patch / fix

  • bitnami lua 5.2.4, 5.3.6, 5.4.1
  • julia Lua_jll 5.3.6+0
  • lua5.3 Debian 14, Debian 13, Debian 12 5.3.6-1
  • lua5.4 Debian 14, Debian 13, Debian 12 5.4.1-1

debian advisories DEBIAN-CVE-2020-24370

  • lua RHEL 8 5.3.4-12.el8
  • lua-libs RHEL 8 5.3.4-12.el8

red hat advisories RHSA-2021:4510

  • lua53 SLE Module for Basesystem 15 SP3, SLE Module for Basesystem 15 SP2, SLE Micro 5.0 5.3.6-3.6.1

suse advisories SUSE-SU-2021:2196-1

  • lua55 openSUSE Tumbleweed 5.5.0~beta1-1.1
  • lua53 openSUSE Leap 15.3 5.3.6-3.6.1
  • lua53 openSUSE Leap 15.2 5.3.6-lp152.5.3.1

opensuse advisories openSUSE-SU-2025:15401-1openSUSE-SU-2021:2196-1openSUSE-SU-2021:0962-1

  • lua AlmaLinux 8 5.3.4-12.el8
  • lua-libs AlmaLinux 8 5.3.4-12.el8

almalinux advisories ALSA-2021:4510

  • lua Rocky Linux 8 5.3.4-12.el8

rocky linux advisories RLSA-2021:4510

  • lua Azure Linux 3.0 5.4.6-1

azure linux advisories AZL-41149

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-2020-24370 updated cvss 5.3

lua: segmentation fault in getlocal and setlocal functions in ldebug.c

  • Red Hat CodeReady Linux Builder (v. 8) lua 5.3.4-12.el8 Red Hat Enterprise Linux AppStream (v. 8) lua 5.3.4-12.el8 Red Hat Enterprise Linux BaseOS (v. 8) lua 5.3.4-12.el8, lua-libs 5.3.4-12.el8
    fixed: vendor fix RHSA-2021:4510
  • Red Hat Enterprise Linux 6 lua Red Hat Enterprise Linux 7 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

3.83% chance of exploitation in the next 30 days, higher than 90% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • lua-users.org http://lua-users.org/lists/lua-l/2020-07/msg00324.html referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
NVD 2.0 5.0 AV:N/AC:L/Au:N/C:N/I:N/A:P
OSV 3.1 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Affected packages

ecosystem package affected fixed in
bitnami lua
>=5.2.0, <5.2.4
>=5.3.0, <5.3.6
>=5.4.0, <5.4.1
5.2.4
5.3.6
5.4.1
julia Lua_jll
<5.3.6+0
5.3.6+0

Classification

Weakness
  • CWE-191 Integer Underflow (Wrap or Wraparound)

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.