ecrecover can return undefined data if signature does not verify
Impact
the ecrecover precompile does not fill the output buffer if the signature does not verify, see https://github.com/ethereum/go-ethereum/blob/b058cf454b3bdc7e770e2b3cec83a0bcb48f55ee/core/vm/contracts.go#L188. however, the ecrecover builtin will still return whatever is at memory location 0.
this means that the if the compiler has been convinced to write to the 0 memory location with specially crafted data (generally, this can happen with a hashmap access or immutable read) just before the ecrecover, a signature check might pass on an invalid signature.
A contract search was performed. Most uses of ecrecover are used for erc2612-style permit implementations, which typically look like:
assert _owner != empty(address)
assert block.timestamp <= _deadline
nonce: uint256 = self.nonces[_owner]
digest: bytes32 = keccak256(
concat(
b"\x19\x01",
self.DOMAIN_SEPARATOR,
keccak256(_abi_encode(PERMIT_TYPEHASH, _owner, _spender, _value, nonce, _deadline))
)
)
assert ecrecover(digest, convert(_v, uint256), convert(_r, uint256), convert(_s, uint256)) == _ownerin this case, the immutable PERMIT_TYPEHASH is loaded into ecrecover's output buffer right before ecrecover(), and so the output of ecrecover() here when the signature is invalid will be the value of PERMIT_TYPEHASH. in this case, since PERMIT_TYPEHASH is not a valid address, it will never compare == to _owner, and so the behaviour is exactly the same as if ecrecover() returned 0 in this case.
in general, a contract could have unexpected behavior (i.e. mistakenly pass this style of signature check) if an immutable representing a real address (ex. OWNER) was read right before the ecrecover operation.
Patches
v0.3.10 (with 019a37ab98ff53f04fecfadf602b6cd5ac748f7f and #3586)
Workarounds
Is there a way for users to fix or remediate the vulnerability without upgrading?
References
Are there any links users can visit to find out more?
Software afectado
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| Plataforma | Paquete | Versiones vulnerables | Corregida en |
|---|---|---|---|
| Python (PyPI) | vyper | < 0.3.10 | 0.3.10 |
Referencias
- https://github.com/vyperlang/vyper/security/advisories/GHSA-f5x6-7qgp-jhf3
- https://github.com/vyperlang/vyper/commit/019a37ab98ff53f04fecfadf602b6cd5ac748f7f
- https://nvd.nist.gov/vuln/detail/CVE-2023-37902
- https://github.com/pypa/advisory-database/tree/main/vulns/vyper/PYSEC-2023-133.yaml
- https://github.com/vyperlang/vyper
- Vector CVSS
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N- Debilidad (CWE)
CWE-252- Plataforma
- Python (PyPI)
- Paquete
vyper- Publicada
- 25.07.2023
- Actualizado
- 11.10.2026 11:20
Fuentes y licencias
OSV / GitHub Advisory Database - PYSEC-2023-133 - PyPA Advisory Database; CC BY 4.0
OSV / GitHub Advisory Database - GHSA-f5x6-7qgp-jhf3 - CC BY 4.0
Historial de vulnerabilidades: vyper
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ecrecover can return undefined data if signature does not verify esta entrada
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