lua-resty-json: Out-of-bounds Read
CVE-2023-3040 is a high-severity out-of-bounds read vulnerability in lua-resty-json from Cloudflare, with a CVSS 3.1 base score of 7.5 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 14 as the first without the flaw, so updating lua-resty-json to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.71% chance of exploitation within 30 days, higher than 54% of scored CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update lua-resty-json to 14 or a later version.
- Read the advisory on github.com for workarounds and exact fixed builds.
- 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 |
|---|---|---|---|
| Cloudflare | lua-resty-json | 1 up to, but not including, 14 | 14 |
Version data comes from the organisation that assigned the CVE. 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
- NoneNo data is disclosed.
- 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:N/I:N/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 3.7 | Low | CNA (cloudflare.com) |
| CVSS 3.1 | 7.5 | High | NVD |
Official description
A debug function in the lua-resty-json package, up to commit id 3ef9492bd3a44d9e51301d6adc3cd1789c8f534a (merged in PR #14) contained an out of bounds access bug that could have allowed an attacker to launch a DoS if the function was used to parse untrusted input data. It is important to note that because this debug function was only used in tests and demos, it was not exploitable in a normal environment.
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.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Advisories
- github.com/cloudflare/lua-resty-json/security/advisories/GHSA-h8rp-9622-83pgThird Party Advisory
Patches and release notes
Recent Out-of-bounds Read vulnerabilities
- 9.1 Critical severity
- 7.5 High severity
- 7.8 High severity
- 7.8 High severity
- 7.5 High severity
- 8.1 High severity
Spotted an error? Tell us.