CVE-2019-6706· NVD / CVE Program· CNA mitre

Lua 5.3.5 has a use-after-free in lua_upvaluejoin in lapi.c.

Noroxi assessment

Priority: Monitor (action score 35/100)

Public proof-of-concept code exists (Exploit-DB); there is no record of exploitation in the wild.
Probability of exploitation in the next 30 days: 17.3% (FIRST EPSS); higher than 97.1% of all records.
Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
Fixed version: lua (AlmaLinux:8) 5.3.4-11.el8; lua-devel (AlmaLinux:8) 5.3.4-11.el8; lua5.3 (Alpine:v3.10) 5.3.5-r2.
Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to lua (AlmaLinux:8) 5.3.4-11.el8; lua-devel (AlmaLinux:8) 5.3.4-11.el8; lua5.3 (Alpine:v3.10) 5.3.5-r2 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

Lua 5.3.5 has a use-after-free in lua_upvaluejoin in lapi.c. For example, a crash outcome might be achieved by an attacker who is able to trigger a debug.upvaluejoin call in which the arguments have certain relationships.

HighCVSS 7.5 · v3.1—Proof of concept Fix available

Published: Jan 23, 2019
Updated: Jun 16, 2026
EPSS: 17.3% · 97th percentile
CWE: CWE-416

Report tools

JSON

Action score

Monitor

Low priority for now.

CVSS: 30 / 40 · 7.5 / 10
CISA KEV: 0 / 30 · Not listed
EPSS: 5 / 30 · 17.3%

Get told when this record changes

Not in KEV: no record of exploitation in the wild
Proof of concept exists, no weaponized module
A fix has been released

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

Vendor	Product	CPE
lua	lua	cpe:2.3:a:lua:lua
canonical	ubuntu linux	cpe:2.3:o:canonical:ubuntu_linux

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

canonical ubuntu linux16.04
canonical ubuntu linux18.04
canonical ubuntu linux18.10
lua lua5.3.5

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

Ecosystem	Package	Affected range	Fix
AlmaLinux:8	lua	before 5.3.4-11.el8	5.3.4-11.el8
AlmaLinux:8	lua-devel	before 5.3.4-11.el8	5.3.4-11.el8
Alpine:v3.10	lua5.3	before 5.3.5-r2	5.3.5-r2
Alpine:v3.14	lua5.4	before 5.3.5-r2	5.3.5-r2
Alpine:v3.7	lua5.3	before 5.3.5-r0	5.3.5-r0
Debian:10	lua5.3	before 5.3.3-1.1+deb10u1	5.3.3-1.1+deb10u1
Debian:12	lua5.3	before 5.3.6-1	5.3.6-1
openSUSE:Leap 15.0	lua53	before 5.3.4-lp150.2.3.1	5.3.4-lp150.2.3.1
Red Hat:enterprise_linux:8::appstream	lua	before 0:5.3.4-11.el8	0:5.3.4-11.el8
Red Hat:enterprise_linux:8::appstream	lua-debuginfo	before 0:5.3.4-11.el8	0:5.3.4-11.el8
Red Hat:enterprise_linux:8::appstream	lua-debugsource	before 0:5.3.4-11.el8	0:5.3.4-11.el8
Red Hat:enterprise_linux:8::appstream	lua-libs-debuginfo	before 0:5.3.4-11.el8	0:5.3.4-11.el8
Red Hat:enterprise_linux:8::baseos	lua-libs	before 0:5.3.4-11.el8	0:5.3.4-11.el8
Red Hat:enterprise_linux:8::crb	lua-devel	before 0:5.3.4-11.el8	0:5.3.4-11.el8
Rocky Linux:8	lua	before 0:5.3.4-11.el8	0:5.3.4-11.el8
SUSE:Linux Enterprise Module for Basesystem 15	lua53	before 5.3.4-3.3.2	5.3.4-3.3.2

Same product

lua: all records

Other highest-scoring records for the same primary product.

CVE-2020-15889Lua 5.4.0 has a getobjname heap-based buffer over-read because youngcollection in lgc.c uses markold for an insufficient number of list memb
40Plan
CVE-2022-28805singlevar in lparser.c in Lua from (including) 5.4.0 up to (excluding) 5.4.4 lacks a certain luaK_exp2anyregup call, leading to a heap-based
37Monitor
CVE-2020-15888Lua through 5.4.0 mishandles the interaction between stack resizes and garbage collection, leading to a heap-based buffer overflow, heap-bas
36Monitor

Published before and after this one in the same product

← EarlierCVE-2014-5461Sep 4, 2014 · Buffer overflow in the vararg functions in ldo.c in Lua 5.1 through 5.2.x before 5.2.3 allows context-dependent attackers to cause a denial
24Monitor
Later →CVE-2020-15945Jul 24, 2020 · Lua 5.4.0 (fixed in 5.4.1) has a segmentation fault in changedline in ldebug.c (e.g., when called by luaG_traceexec) because it incorrectly
22Monitor
Later →CVE-2020-24342Aug 13, 2020 · Lua through 5.4.0 allows a stack redzone cross in luaO_pushvfstring because a protection mechanism wrongly calls luaD_callnoyield twice in a
31Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / package	Fixed version	Source
almalinux:lua	5.3.4-11.el8 · AlmaLinux:8	Package registry (OSV)
almalinux:lua-devel	5.3.4-11.el8 · AlmaLinux:8	Package registry (OSV)
alpine:lua5.3	5.3.5-r2 · Alpine:v3.10	Package registry (OSV)
alpine:lua5.4	5.3.5-r2 · Alpine:v3.14	Package registry (OSV)
debian:lua5.3	5.3.6-1 · Debian:12	Package registry (OSV)
opensuse:lua53	5.3.4-lp150.2.3.1 · openSUSE:Leap 15.0	Package registry (OSV)
red hat:lua	0:5.3.4-11.el8 · Red Hat:enterprise_linux:8::appstream	Package registry (OSV)
red hat:lua-debuginfo	0:5.3.4-11.el8 · Red Hat:enterprise_linux:8::appstream	Package registry (OSV)
red hat:lua-debugsource	0:5.3.4-11.el8 · Red Hat:enterprise_linux:8::appstream	Package registry (OSV)
red hat:lua-devel	0:5.3.4-11.el8 · Red Hat:enterprise_linux:8::crb	Package registry (OSV)
red hat:lua-libs	0:5.3.4-11.el8 · Red Hat:enterprise_linux:8::baseos	Package registry (OSV)
red hat:lua-libs-debuginfo	0:5.3.4-11.el8 · Red Hat:enterprise_linux:8::appstream	Package registry (OSV)
rocky linux:lua	0:5.3.4-11.el8 · Rocky Linux:8	Package registry (OSV)
suse:lua53	5.3.4-3.3.2 · SUSE:Linux Enterprise Module for Basesystem 15	Package registry (OSV)

Exploit status

Proof of concept available

A public proof of concept or detection signature exists. Exploit knowledge is out there; don't delay patching.

Evidence

Exploit-DB entry ×1

Noroxi does not host or link to exploit code. Metasploit module names and Nuclei template ids are shown (names, not code); Exploit-DB entries and PoC repositories are given as counts only.

Public exploit evidence
Source	Kind	Date
Exploit-DB entry	dos	2019-01-25

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

PublishedJan 23, 2019
First PoCJan 25, 2019+1 d
TodayOct 23, 2026+2830 d

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

lua/luacommit 89aee84

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

TR-20-905 · Oct 30, 2020(OpenShift Güvenlik Güncellemesi)

All national notices →

Technical details

Attack conditions

Anyone who can reach it over the internet can trigger it.
No account or password is required.
No user action is required.
No special conditions are required; it is repeatable.

If successful

Confidentiality: none
Integrity: none
Availability: high · the service can be disrupted

Attack vector: Network
Attack complexity: Low
Privileges required: None
User interaction: None
Scope: Unchanged
Confidentiality impact: None
Integrity impact: None
Availability impact: High

Weakness class (CWE)

CWE-416 · Use After Free

CVSS vector

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

nvd-primary

Root cause

After a memory region is freed, another reference pointing to it is still used. By then, the same region may have been allocated for different data.

The bug in code

The whole CWE-416 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

1free(dev->buf);
2/* ... another thread is still running ... */
3process(dev->buf);

Fixed

1lock(&dev->lock);
2free(dev->buf);
3dev->buf = NULL;
4unlock(&dev->lock);

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

Fix✗ → ✓Sep 28, 2026, 10:45 PM UTC

For records you follow, these changes also arrive as notifications. →

References

lua-users.org/lists/lua-l/2019-01/msg00039.html

Show all references (3 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records