era-compiler-vyper: Loop with Unreachable Exit Condition
CVE-2024-43366 is a critical-severity loop with unreachable exit condition vulnerability in era-compiler-vyper from Matter-labs, 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 1.5.3 as the first without the flaw, so updating era-compiler-vyper to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.51% chance of exploitation within 30 days, which is low compared with other CVEs.
Critical severity: a successful attack would have severe impact.
What to do
- Update era-compiler-vyper to 1.5.3 or a later version.
- Update Zkvyper to 1.5.3 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 |
|---|---|---|---|
| Matter-labs | era-compiler-vyper | >= 1.3.12, < 1.5.3; 1.3.12 up to, but not including, 1.5.3 | 1.5.3 |
| Matter-labs | Zkvyper | 1.3.12 up to, but not including, 1.5.3 | 1.5.3 |
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
- HighData or code can be modified at will.
- 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:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 7.5 | High | CNA (github.com) |
| CVSS 3.1 | 9.1 | Critical | NVD |
Official description
zkvyper is a Vyper compiler. Starting in version 1.3.12 and prior to version 1.5.3, since LLL IR has no Turing-incompletness restrictions, it is compiled to a loop with a much more late exit condition. It leads to a loss of funds or other unwanted behavior if the loop body contains it. However, more real-life use cases like iterating over an array are not affected. No contracts were affected by this issue, which was fixed in version 1.5.3. Upgrading and redeploying affected contracts is the only way to avoid the vulnerability.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Loop with Unreachable Exit Condition
The product contains an iteration or loop with an exit condition that cannot be reached, i.e., an infinite loop.
More Loop with Unreachable Exit Condition vulnerabilities (CWE-835)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: poc, automatable: yes, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Advisories
- github.com/matter-labs/era-compiler-vyper/security/advisories/GHSA-8j77-7rrv-6pxxExploit, Third Party Advisory
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