CVE-2024-22419

concat built-in can corrupt memory in vyper

Published Jan 18, 2024 CVSS 3.1 · 7.3 High EPSS < 1% KEV · Not listed

Description

Vyper is a Pythonic Smart Contract Language for the Ethereum Virtual Machine. The `concat` built-in can write over the bounds of the memory buffer that was allocated for it and thus overwrite existing valid data. The root cause is that the `build_IR` for `concat` doesn't properly adhere to the API of copy functions (for `>=0.3.2` the `copy_bytes` function). A contract search was performed and no vulnerable contracts were found in production. The buffer overflow can result in the change of semantics of the contract. The overflow is length-dependent and thus it might go unnoticed during contract testing. However, certainly not all usages of concat will result in overwritten valid data as we require it to be in an internal function and close to the return statement where other memory allocations don't occur. This issue has been addressed in 0.4.0.

Analysis

No analysis available yet

Affected Products

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions

vyperlang

vyper

affected

Version	Status	Constraints
`< 0.4.0`	affected	—

Configuration 1 [-]

cpe:2.3:a:vyperlang:vyper:*:*:*:*:*:python:*:*

No data.

No data available yet.

Remediation

No remediation available yet

Tracking

Advisories

Source	ID	Title
EUVD	EUVD-2024-0173	Vyper is a Pythonic Smart Contract Language for the Ethereum Virtual Machine. The `concat` built-in can write over the bounds of the memory buffer that was allocated for it and thus overwrite existing valid data. The root cause is that the `build_IR` for `concat` doesn't properly adhere to the API of copy functions (for `>=0.3.2` the `copy_bytes` function). A contract search was performed and no vulnerable contracts were found in production. The buffer overflow can result in the change of semantics of the contract. The overflow is length-dependent and thus it might go unnoticed during contract testing. However, certainly not all usages of concat will result in overwritten valid data as we require it to be in an internal function and close to the return statement where other memory allocations don't occur. This issue has been addressed in 0.4.0.
Github GHSA	GHSA-2q8v-3gqq-4f8p	concat built-in can corrupt memory in vyper

Metrics

No CVSS v4.0

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact Low

Integrity Impact Low

Availability Impact Low

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

Exploit prediction score: < 1% (0.770% probability within 30 days)

Exploitation poc

Automatable yes

Technical Impact partial

References

Link	Providers
https://github.com/vyperlang/vyper/commit/55e18f6d128b2da8986adbbcccf1cd59a4b9ad6f
https://github.com/vyperlang/vyper/issues/3737
https://github.com/vyperlang/vyper/security/advisories/GHSA-2q8v-3gqq-4f8p

History

Jun 2, 2025 8:15 PM Scoring metrics updated View changes

Type	Values Removed	Values Added
Metrics		ssvc `{'options': {'Automatable': 'yes', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}`

Oct 9, 2024 7:45 PM Description updated View changes

Type	Values Removed	Values Added
Description	Vyper is a Pythonic Smart Contract Language for the Ethereum Virtual Machine. The `concat` built-in can write over the bounds of the memory buffer that was allocated for it and thus overwrite existing valid data. The root cause is that the `build_IR` for `concat` doesn't properly adhere to the API of copy functions (for `>=0.3.2` the `copy_bytes` function). A contract search was performed and no vulnerable contracts were found in production. The buffer overflow can result in the change of semantics of the contract. The overflow is length-dependent and thus it might go unnoticed during contract testing. However, certainly not all usages of concat will result in overwritten valid data as we require it to be in an internal function and close to the return statement where other memory allocations don't occur. This issue has been addressed in commit `55e18f6d1` which will be included in future releases. Users are advised to update when possible.	Vyper is a Pythonic Smart Contract Language for the Ethereum Virtual Machine. The `concat` built-in can write over the bounds of the memory buffer that was allocated for it and thus overwrite existing valid data. The root cause is that the `build_IR` for `concat` doesn't properly adhere to the API of copy functions (for `>=0.3.2` the `copy_bytes` function). A contract search was performed and no vulnerable contracts were found in production. The buffer overflow can result in the change of semantics of the contract. The overflow is length-dependent and thus it might go unnoticed during contract testing. However, certainly not all usages of concat will result in overwritten valid data as we require it to be in an internal function and close to the return statement where other memory allocations don't occur. This issue has been addressed in 0.4.0.