Lua: Out-of-bounds Read
CVE-2022-28805 is a critical-severity out-of-bounds read vulnerability in Lua, with a CVSS 3.1 base score of 9.1 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists version 5.4.5 as the first without the flaw, so updating Lua to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 2.98% chance of exploitation within 30 days, higher than 87% of scored CVEs.
Critical severity: a successful attack would have severe impact.
What to do
- Update Lua to 5.4.5 or a later version.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Lua | Lua | 5.4.0 up to, but not including, 5.4.5 | 5.4.5 |
| Fedora Project | Fedora | 35; 36 | Not stated |
Version data comes from NVD's product matching. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- NoneNothing can be modified.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 9.1 | Critical | NVD |
| CVSS 2.0 | 6.4 | Medium | NVD |
Official description
singlevar 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 buffer over-read that might affect a system that compiles untrusted Lua code.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Out-of-bounds Read
The product reads data past the end, or before the beginning, of the intended buffer.
How developers prevent this class of flaw
- Use a language that provides appropriate memory abstractions.
Timeline
- CVE record published.
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
- github.com/lua/lua/commit/1f3c6f4534c6411313361697d98d1145a1f030faThird Party Advisory
Third-party and government advisories
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/RJNJ66IFDUKWJJZXHGOL…Third Party Advisory
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/UHYZOEFDVLVAD6EEP4CD…Third Party Advisory
- security.gentoo.org/glsa/202305-23Third Party Advisory
Technical write-ups (may include proof of concept)
- lua-users.org/lists/lua-l/2022-02/msg00001.htmlExploit, Mailing List, Third Party Advisory
- lua-users.org/lists/lua-l/2022-02/msg00070.htmlExploit, Mailing List, Third Party Advisory
- lua-users.org/lists/lua-l/2022-04/msg00009.htmlExploit, Mailing List, Third Party Advisory
Recent Out-of-bounds Read vulnerabilities
- 7.5 High severity
- 9.8 Critical severity
- 7.8 High severity
- 7.1 High severity
- 7.1 High severity
- 7.1 High severity
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