LuajitApplication

CVE-2019-19391

CRITICAL · 9.1 CVSS v3.1 Published 2019-11-29
Fix available
A fix is available. Upgrade to 2.1.2 or later.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click Patch available

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
In LuaJIT through 2.0.5, as used in Moonjit before 2.1.2 and other products, debug.getinfo has a type confusion issue that leads to arbitrary memory write or read operations, because certain cases involving valid stack levels and > options are mishandled. NOTE: The LuaJIT project owner states that the debug libary is unsafe by definition and that this is not a vulnerability. When LuaJIT was originally developed, the expectation was that the entire debug library had no security guarantees and thus it made no sense to assign CVEs. However, not all users of later LuaJIT derivatives share this perspective

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis
How this class of weakness works · CWE-843

A resource is accessed as one type when it was actually allocated as another, so the code misreads memory layout — in interpreters and language runtimes this is frequently a direct path to code execution. It often arises from unchecked casts on attacker-influenced objects. The fix is strict type checks before casts and memory-safe access patterns.

General guidance for the type confusion class — the official description and references above are authoritative for this specific CVE. Want a bespoke review and a reviewed fix? Ask our team →

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
LuajitApplication
Affected:<= 2.0.5
MoonjitApplication
Affected:< 2.1.2

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
None

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

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 2.1.2 or later
Fixed in 2.1.2
Vendor patch github.com →
Recommended fix High confidence

LuaJIT v2.1.0+ or Moonjit 2.1.2+

  1. 1. Identify which LuaJIT or Moonjit version is currently in use by checking the runtime or library version
  2. 2. For LuaJIT users: Upgrade to LuaJIT version 2.1.0 or later (the fix is incorporated in the v2.1 release)
  3. 3. For Moonjit users: Upgrade to Moonjit version 2.1.2 or later
  4. 4. After upgrade, verify the new version is running by checking debug.getinfo behavior or version string
  5. 5. Test that existing Lua scripts using debug.getinfo function correctly after the upgrade
Caveat The LuaJIT project notes the debug library is intentionally unsafe by design; however, the type confusion fix may change behavior in edge cases where invalid stack levels or format options were previously mishandled

Generated from the published advisory — verify against the referenced sources before acting.

We can perform the upgrade in your staging environment and verify nothing breaks — typical engagement from $2,300. Get the upgrade done

Scan for this in your stack

Free · runs locally
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2019-19391 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
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