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CVE-2023-30629

HIGH
Published 2023-04-24T21:58:00.227Z
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CVSS Score

V3.1
7.5
/10
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Base Score Metrics
Exploitability: N/A Impact: N/A

EPSS Score

v2025.03.14
0.002
probability
of exploitation in the wild

There is a 0.2% chance that this vulnerability will be exploited in the wild within the next 30 days.

Updated: 2025-06-25
Exploit Probability
Percentile: 0.430
Higher than 43.0% of all CVEs

Attack Vector Metrics

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED

Impact Metrics

Confidentiality
NONE
Integrity
HIGH
Availability
NONE

Description

Vyper is a Pythonic Smart Contract Language for the ethereum virtual machine. In versions 0.3.1 through 0.3.7, the Vyper compiler generates the wrong bytecode. Any contract that uses the `raw_call` with `revert_on_failure=False` and `max_outsize=0` receives the wrong response from `raw_call`. Depending on the memory garbage, the result can be either `True` or `False`. A patch is available and, as of time of publication, anticipated to be part of Vyper 0.3.8. As a workaround, one may always put `max_outsize>0`.

Understanding This Vulnerability

This Common Vulnerabilities and Exposures (CVE) entry provides detailed information about a security vulnerability that has been publicly disclosed. CVEs are standardized identifiers assigned by MITRE Corporation to track and catalog security vulnerabilities across software and hardware products.

The severity rating (HIGH) indicates the potential impact of this vulnerability based on the CVSS (Common Vulnerability Scoring System) framework. Higher severity ratings typically indicate vulnerabilities that could lead to more significant security breaches if exploited. Security teams should prioritize remediation efforts based on severity, exploit availability, and the EPSS (Exploit Prediction Scoring System) score, which predicts the likelihood of exploitation in the wild.

If this vulnerability affects products or systems in your infrastructure, we recommend reviewing the affected products section, checking for available patches or updates from vendors, and implementing recommended workarounds or solutions until a permanent fix is available. Organizations should also monitor security advisories and threat intelligence feeds for updates about active exploitation of this vulnerability.

Available Exploits

No exploits available for this CVE.

Related News

No news articles found for this CVE.

Affected Products

References

GitHub Security Advisories

Community-driven vulnerability intelligence from GitHub

✓ GitHub Reviewed HIGH

Incorrect success value returned in vyper

GHSA-w9g2-3w7p-72g9

Advisory Details

### Background During the audit of [Lido's Gate Seals](https://github.com/lidofinance/gate-seals) code [statemind](https://statemind.io) team identified a weird behavior of the code that uses `raw_call`: https://github.com/lidofinance/gate-seals/blob/051593e74df01a4131c485b4fda52e691cd4b7d8/contracts/GateSeal.vy#L164 . Construction like this: ```vyper success = raw_call( sealable, _abi_encode(SEAL_DURATION_SECONDS, method_id=method_id("pauseFor(uint256)")), revert_on_failure=False ) ``` was not fully documented: https://docs.vyperlang.org/en/v0.3.7/built-in-functions.html#raw_call . The documentation says that: if `max_outsize=0` it should return nothing and then it says that if `revert_on_failure=False` it should return a `success` flag in the tuple of response, but what if `max_outsize=0` and `revert_on_failure=False`. <img width="715" alt="image" src="https://user-images.githubusercontent.com/22330612/232125364-d2b3bbac-0b4f-40cb-80ff-f55d8eafef44.png"> So the team started researching what exactly happened in that case, after some research we found that the Vyper compiler generates the wrong bytecode in that case, it generates the sequence: ``` CALL // call MLOAD // MLOAD is wrong since the CALL result is already stored in the stack ``` ### Impact Example of buggy code: ```vyper @external def returnSome(calling: address, a: uint256) -> bool: success: bool = false success = raw_call( calling, _abi_encode(a, method_id=method_id("a(uint256)")), revert_on_failure=False ) ``` any contract that uses the `raw_call` with `revert_on_failure=False` and `max_outsize=0` receives the wrong response from `raw_call`. Depending on the memory garbage, the result can be either `True` or `False`. ### Patches Fix by @charles-cooper https://github.com/vyperlang/vyper/commit/851f7a1b3aa2a36fd041e3d0ed38f9355a58c8ae ### Workarounds The simple workaround is always to put `max_outsize>0`. Workaround example https://github.com/lidofinance/gate-seals/pull/5/files ### References Lido's fix: https://github.com/lidofinance/gate-seals/pull/5/files

Affected Packages

PyPI vyper
ECOSYSTEM: ≥0.3.1 <0.3.8

CVSS Scoring

CVSS Score

7.5

CVSS Vector

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

Advisory provided by GitHub Security Advisory Database. Published: April 24, 2023, Modified: November 19, 2024

References

Published: 2023-04-24T21:58:00.227Z
Last Modified: 2025-02-12T16:35:42.775Z
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