ghsa-ppx5-q359-pvwj
Vulnerability from github
Summary
When looping over a range
of the form range(start, start + N)
, if start
is negative, the execution will always revert.
Details
This issue is caused by an incorrect assertion inserted by the code generation of the range (stmt.parse_For_range()
):
https://github.com/vyperlang/vyper/blob/9136169468f317a53b4e7448389aa315f90b95ba/vyper/codegen/stmt.py#L286-L287
This assertion was introduced in https://github.com/vyperlang/vyper/commit/3de1415ee77a9244eb04bdb695e249d3ec9ed868 to fix https://github.com/advisories/GHSA-6r8q-pfpv-7cgj. The issue arises when start
is signed, instead of using sle
, le
is used and start
is interpreted as an unsigned integer for the comparison. If it is a negative number, its 255th bit is set to 1
and is hence interpreted as a very large unsigned integer making the assertion always fail.
PoC
Vyper
@external
def foo():
x:int256 = min_value(int256)
# revert when it should not since we have the following assertion that fails:
# [assert, [le, min_value(int256), max_value(int256) + 1 - 10]],
for i in range(x, x + 10):
pass
Patches
patched in v0.4.0, specifically, https://github.com/vyperlang/vyper/pull/3679 disallows this form of range()
.
Impact
Any contract having a range(start, start + N)
where start
is a signed integer with the possibility for start
to be negative is affected. If a call goes through the loop while supplying a negative start
the execution will revert.
{ "affected": [ { "package": { "ecosystem": "PyPI", "name": "vyper" }, "ranges": [ { "events": [ { "introduced": "0.3.8" }, { "fixed": "0.4.0" } ], "type": "ECOSYSTEM" } ] } ], "aliases": [ "CVE-2024-32481" ], "database_specific": { "cwe_ids": [ "CWE-681" ], "github_reviewed": true, "github_reviewed_at": "2024-04-25T19:53:43Z", "nvd_published_at": "2024-04-25T17:15:50Z", "severity": "MODERATE" }, "details": "### Summary\n\nWhen looping over a `range` of the form `range(start, start + N)`, if `start` is negative, the execution will always revert.\n \n### Details\n\nThis issue is caused by an incorrect assertion inserted by the code generation of the range (`stmt.parse_For_range()`):\n\nhttps://github.com/vyperlang/vyper/blob/9136169468f317a53b4e7448389aa315f90b95ba/vyper/codegen/stmt.py#L286-L287\n\nThis assertion was introduced in https://github.com/vyperlang/vyper/commit/3de1415ee77a9244eb04bdb695e249d3ec9ed868 to fix https://github.com/advisories/GHSA-6r8q-pfpv-7cgj. The issue arises when `start` is signed, instead of using `sle`, `le` is used and `start` is interpreted as an unsigned integer for the comparison. If it is a negative number, its 255th bit is set to `1` and is hence interpreted as a very large unsigned integer making the assertion always fail. \n### PoC\n\n```Vyper\n@external\ndef foo():\n x:int256 = min_value(int256)\n # revert when it should not since we have the following assertion that fails:\n # [assert, [le, min_value(int256), max_value(int256) + 1 - 10]],\n for i in range(x, x + 10):\n pass\n```\n\n### Patches\n\npatched in v0.4.0, specifically, https://github.com/vyperlang/vyper/pull/3679 disallows this form of `range()`.\n\n### Impact\n\nAny contract having a `range(start, start + N)` where `start` is a signed integer with the possibility for `start` to be negative is affected. If a call goes through the loop while supplying a negative `start` the execution will revert.", "id": "GHSA-ppx5-q359-pvwj", "modified": "2024-04-25T19:53:43Z", "published": "2024-04-25T19:53:43Z", "references": [ { "type": "WEB", "url": "https://github.com/vyperlang/vyper/security/advisories/GHSA-ppx5-q359-pvwj" }, { "type": "ADVISORY", "url": "https://nvd.nist.gov/vuln/detail/CVE-2024-32481" }, { "type": "WEB", "url": "https://github.com/vyperlang/vyper/commit/3de1415ee77a9244eb04bdb695e249d3ec9ed868" }, { "type": "WEB", "url": "https://github.com/vyperlang/vyper/commit/5319cfbe14951e007ccdb323257e5ada869b35d5" }, { "type": "PACKAGE", "url": "https://github.com/vyperlang/vyper" }, { "type": "WEB", "url": "https://github.com/vyperlang/vyper/blob/9136169468f317a53b4e7448389aa315f90b95ba/vyper/codegen/stmt.py#L286-L287" } ], "schema_version": "1.4.0", "severity": [ { "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N", "type": "CVSS_V3" } ], "summary": "vyper\u0027s range(start, start + N) reverts for negative numbers" }
Sightings
Author | Source | Type | Date |
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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.