CVE-2023-28431 | BDVDB-2026-197909 Detail
paritytechfrontier
Description#
Frontier is an Ethereum compatibility layer for Substrate. Frontier's `modexp` precompile uses `num-bigint` crate under the hood. In the implementation prior to pull request 1017, the cases for modulus being even and modulus being odd are treated separately. Odd modulus uses the fast Montgomery multiplication, and even modulus uses the slow plain power algorithm. This gas cost discrepancy was not accounted for in the `modexp` precompile, leading to possible denial of service attacks. No fixes for `num-bigint` are currently available, and thus this issue is fixed in the short term by raising the gas costs for even modulus, and in the long term fixing it in `num-bigint` or switching to another modexp implementation. The short-term fix for Frontier is deployed at pull request 1017. There are no known workarounds aside from applying the fix.
Impact#
Per CVSS v3.1: confidentiality impact none, integrity impact none, availability impact high. Attack vector: network.
Weaknesses#
- CWE-682 Incorrect Calculation
References#
- https://github.com/paritytech/frontier/security/advisories/GHSA-fcmm-54jp-7vf6
- https://github.com/paritytech/frontier/pull/1017
- https://github.com/paritytech/frontier/commit/5af12e94d7dfc8a0208a290643a800f55de7b219
- https://github.com/rust-num/num-bigint/blob/6f2b8e0fc218dbd0f49bebb8db2d1a771fe6bafa/src/biguint/power.rs#L134
Exploit#
No public exploit known
History#
- Version 1Record published in the CVE List.
- Version 2Most recent update recorded in the CVE List.