ghsa-9p8r-4xp4-gw5w
Vulnerability from github
Summary
If an excessively large value is specified as the starting index for an array in _abi_decode, it can cause the read position to overflow. This results in the decoding of values outside the intended array bounds, potentially leading to bugs in contracts that use arrays within _abi_decode. The advisory has been assigned low severity, because it is only observable if there is a memory write between two invocations of abi_decode on the same input.
Proof of Concept
```vyper event Pwn: pass
@external def f(x: Bytes[32 * 3]): a: Bytes[32] = b"foo" y: Bytes[32 * 3] = x
decoded_y1: Bytes[32] = _abi_decode(y, Bytes[32])
a = b"bar"
decoded_y2: Bytes[32] = _abi_decode(y, Bytes[32])
if decoded_y1 != decoded_y2:
log Pwn()
```
Sending the following calldata results in Pwn being emitted.
0xd45754f8
0000000000000000000000000000000000000000000000000000000000000020
0000000000000000000000000000000000000000000000000000000000000060
ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffa0
Patches
Patched in https://github.com/vyperlang/vyper/pull/3925, https://github.com/vyperlang/vyper/pull/4091, https://github.com/vyperlang/vyper/pull/4144, https://github.com/vyperlang/vyper/pull/4060.
{
"affected": [
{
"package": {
"ecosystem": "PyPI",
"name": "vyper"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "0.4.0"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2024-26149"
],
"database_specific": {
"cwe_ids": [
"CWE-119",
"CWE-120"
],
"github_reviewed": true,
"github_reviewed_at": "2024-02-26T20:11:07Z",
"nvd_published_at": "2024-02-26T20:19:05Z",
"severity": "LOW"
},
"details": "## Summary\n\nIf an excessively large value is specified as the starting index for an array in `_abi_decode`, it can cause the read position to overflow. This results in the decoding of values outside the intended array bounds, potentially leading to bugs in contracts that use arrays within `_abi_decode`. The advisory has been assigned low severity, because it is only observable if there is a memory write between two invocations of `abi_decode` on the same input.\n\n## Proof of Concept\n\n```vyper\nevent Pwn:\n pass\n\n@external\ndef f(x: Bytes[32 * 3]):\n a: Bytes[32] = b\"foo\"\n y: Bytes[32 * 3] = x\n\n decoded_y1: Bytes[32] = _abi_decode(y, Bytes[32])\n a = b\"bar\"\n decoded_y2: Bytes[32] = _abi_decode(y, Bytes[32])\n\n if decoded_y1 != decoded_y2:\n log Pwn()\n```\n\nSending the following calldata results in `Pwn` being emitted. \n\n```\n0xd45754f8\n0000000000000000000000000000000000000000000000000000000000000020\n0000000000000000000000000000000000000000000000000000000000000060\nffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffa0\n```\n\n### Patches\nPatched in https://github.com/vyperlang/vyper/pull/3925, https://github.com/vyperlang/vyper/pull/4091, https://github.com/vyperlang/vyper/pull/4144, https://github.com/vyperlang/vyper/pull/4060.",
"id": "GHSA-9p8r-4xp4-gw5w",
"modified": "2024-06-18T15:16:24Z",
"published": "2024-02-26T20:11:07Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/vyperlang/vyper/security/advisories/GHSA-9p8r-4xp4-gw5w"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2024-26149"
},
{
"type": "PACKAGE",
"url": "https://github.com/vyperlang/vyper"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N",
"type": "CVSS_V3"
}
],
"summary": "Vyper\u0027s `_abi_decode` vulnerable to Memory Overflow"
}
Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.