CVE-2019-6706

HIGH

Lua 5.3.5 - Use-After-Free in lua_upvaluejoin

Title source: llm
STIX 2.1

Exploitation Summary

EIP tracks 1 public exploit for CVE-2019-6706. PoCs published by Fady Mohammed Osman.

AI-analyzed exploit summary The writeup describes a heap use-after-free vulnerability in Lua 5.3.5's `lua_upvaluejoin` function, triggered when the same function and upvalue index are provided, leading to a crash. It includes technical details, PoC code, and references to the fix.

Description

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.

Exploits (1)

exploitdb WRITEUP
by Fady Mohammed Osman · textdosmultiple
https://www.exploit-db.com/exploits/46246

The writeup describes a heap use-after-free vulnerability in Lua 5.3.5's `lua_upvaluejoin` function, triggered when the same function and upvalue index are provided, leading to a crash. It includes technical details, PoC code, and references to the fix.

Classification
Writeup 100%
Attack Type
Dos
Complexity
Moderate
Reliability
Reliable
Target: Lua 5.3.5
No auth needed
Prerequisites: Lua 5.3.5 installation · ability to execute Lua code
devstral-2 · analyzed Feb 16, 2026 Full analysis →

Scores

CVSS v3 7.5
EPSS 0.1722
EPSS Percentile 96.7%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Details

CWE
CWE-416
Status published
Products (4)
canonical/ubuntu_linux 16.04
canonical/ubuntu_linux 18.04
canonical/ubuntu_linux 18.10
lua/lua 5.3.5
Published Jan 23, 2019
Tracked Since Feb 18, 2026