CVE-2021-48020
Vyper before 0.3.0 Memory Corruption via Internal Function Calls in Arrays
Description
Vyper from 0.1.0b4 before 0.3.0 contains a memory corruption vulnerability caused by an incorrect stack tip pointer when internal function calls are performed inside arrays. Contracts placing internal calls in nested array elements, external call arguments, struct literals, or raw_log topics can have memory corrupted, producing incorrect contract behavior.
INFO
Published Date :
Oct. 21, 2026, 1:17 a.m.
Last Modified :
Oct. 21, 2026, 1:17 a.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | MEDIUM | 83251b91-4cc7-4094-a5c7-464a1b83ea10 | ||||
| CVSS 3.1 | MEDIUM | MITRE-CVE | ||||
| CVSS 3.1 | MEDIUM | [email protected] | ||||
| CVSS 4.0 | HIGH | 83251b91-4cc7-4094-a5c7-464a1b83ea10 | ||||
| CVSS 4.0 | HIGH | [email protected] |
Solution
- Update Vyper to a secure version.
- Review and test contract code for safe internal calls.
- Deploy updated contracts.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2021-48020.
| URL | Resource |
|---|---|
| https://github.com/vyperlang/vyper/security/advisories/GHSA-22wc-c9wj-6q2v | |
| https://www.vulncheck.com/advisories/vyper-before-0.3.0-memory-corruption-via-internal-function-calls-in-arrays |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2021-48020 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2021-48020
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2021-48020 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2021-48020 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
New CVE Received by [email protected]
Oct. 21, 2026
Action Type Old Value New Value Added Description Vyper from 0.1.0b4 before 0.3.0 contains a memory corruption vulnerability caused by an incorrect stack tip pointer when internal function calls are performed inside arrays. Contracts placing internal calls in nested array elements, external call arguments, struct literals, or raw_log topics can have memory corrupted, producing incorrect contract behavior. Added CVSS V4.0 AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X Added CVSS V3.1 AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:L Added CWE CWE-787 Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2021/48xxx/CVE-2021-48020.json">CVE-2021-48020</a> Added Reference https://github.com/vyperlang/vyper/security/advisories/GHSA-22wc-c9wj-6q2v Added Reference https://www.vulncheck.com/advisories/vyper-before-0.3.0-memory-corruption-via-internal-function-calls-in-arrays