# Incorrect success value returned in vyper

Advisory record · `GHSA-w9g2-3w7p-72g9`

- **Identifiers:** `GHSA-w9g2-3w7p-72g9` · `CVE-2023-30629` · `PYSEC-2023-131`
- **State:** Confirmed
- **Severity:** CVSS 7.5 High
- **Critical:** No
- **Weakness (CWE):** [CWE-670](https://cwe.mitre.org/data/definitions/670.html)
- **Tags:** [CWE-670](https://agentprime.io/advisories/tag/cwe-670.md)
- **Published:** 24 Apr 2023
- **Updated:** 10 Sept 2026
- **Reviewed by a person:** No

Published by the GitHub Advisory Database at 24 Apr 2023, 22:33 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

## Affected packages

- `vyper` (PyPI): affected `>=0.3.1, <0.3.8`; fixed in `0.3.8`

## Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

> Vyper versions from 0.3.1 before 0.3.8 are affected: when a contract calls raw_call with both max_outsize=0 and revert_on_failure=False, the compiler generates incorrect bytecode, so the returned success flag can be either True or False depending on memory contents. An attacker does not need access; any contract using this call pattern receives the wrong result, which can affect its logic. Upgrade to Vyper 0.3.8. As a workaround, set max_outsize to a value greater than 0.

Written 5 Nov 2026.

## Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

## Severity and exploitation

- 7.5 High, CVSS 3.1: `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N`, from CNA (GitHub_M)

- **CISA KEV:** Not listed.
- **EPSS:** 0.0088, the 59th percentile, on 7 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

## Timeline

- 31 Oct 2026, 14:36 UTC: First seen by agentprime
- 31 Oct 2026, 14:36 UTC: [Confirmed by OSV](https://osv.dev/vulnerability/GHSA-w9g2-3w7p-72g9)

## Sources

- [GitHub Advisory Database: GHSA-w9g2-3w7p-72g9](https://github.com/advisories/GHSA-w9g2-3w7p-72g9)
- [OSV: GHSA-w9g2-3w7p-72g9](https://osv.dev/vulnerability/GHSA-w9g2-3w7p-72g9)
- <https://github.com/vyperlang/vyper/security/advisories/GHSA-w9g2-3w7p-72g9>
- <https://nvd.nist.gov/vuln/detail/CVE-2023-30629>
- <https://github.com/lidofinance/gate-seals/pull/5/files>
- <https://github.com/vyperlang/vyper/commit/851f7a1b3aa2a36fd041e3d0ed38f9355a58c8ae>
- <https://docs.vyperlang.org/en/v0.3.7/built-in-functions.html#raw_call>
- <https://github.com/lidofinance/gate-seals/blob/051593e74df01a4131c485b4fda52e691cd4b7d8/contracts/GateSeal.vy#L164>
- <https://github.com/pypa/advisory-database/tree/main/vulns/vyper/PYSEC-2023-131.yaml>
- <https://github.com/vyperlang/vyper>

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.

## Check whether this affects you

A Match means an installed version is in the affected range above. Most don’t affect the app; agentprime hasn’t analysed this one yet.

- With the agentprime MCP server (<https://api.agentprime.io/mcp>), ask your agent to check the project: `check_lockfile` sends a lockfile, `check_packages` a list of installed packages, and both return the Matches and the upgrades that clear them. `get_advisory` returns this record. Setup: <https://agentprime.io/mcp.md>
- In a browser: <https://agentprime.io/check/> reads your lockfile in the browser, never uploading it.
- Whether it touches your code, with file and line: the Claude Code plugin, <https://agentprime.io/plugin.md>
- As JSON: <https://api.agentprime.io/v1/advisories/GHSA-w9g2-3w7p-72g9>, or `POST https://api.agentprime.io/v1/match` with your packages (<https://agentprime.io/api.md>)

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The web page: <https://agentprime.io/advisories/GHSA-w9g2-3w7p-72g9/>. Everything for agents: <https://agentprime.io/llms.txt>.