CVE-2023-28431
CVE-2023-28431 is a high-severity vulnerability in Parity Frontier with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-682.
Key facts
- Severity: High (CVSS 3.x base score 7.5)
- EPSS exploit prediction: 1% (55th percentile)
- Actively exploited: Not listed in CISA KEV
- Weakness: CWE-682
- Affected product: Parity Frontier
- Published:
- Last modified:
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.
Frequently asked questions
- What is CVE-2023-28431?
- 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.
- How severe is CVE-2023-28431?
- CVE-2023-28431 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
- Is CVE-2023-28431 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (55th percentile), an estimate of the probability of exploitation in the next 30 days.
- What products are affected by CVE-2023-28431?
- CVE-2023-28431 affects Parity Frontier. See the affected-products list for the exact vulnerable versions.
- How do I fix CVE-2023-28431?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
- When was CVE-2023-28431 published?
- CVE-2023-28431 was published on 2023-03-22 and last updated on 2026-06-17.
References
- https://github.com/paritytech/frontier/commit/5af12e94d7dfc8a0208a290643a800f55de7b219
- https://github.com/paritytech/frontier/pull/1017
- https://github.com/paritytech/frontier/security/advisories/GHSA-fcmm-54jp-7vf6
- https://github.com/rust-num/num-bigint/blob/6f2b8e0fc218dbd0f49bebb8db2d1a771fe6bafa/src/biguint/power.rs#L134
Affected products (1)
- cpe:2.3:a:parity:frontier:*:*:*:*:*:*:*:*
More vulnerabilities in Parity Frontier
- CVE-2023-45130 — High (CVSS 7.5): Frontier is Substrate's Ethereum compatibility layer. Prior to commit aea528198b3b226e0d20cce878551fd4c0e3d5d0, at the…
- CVE-2022-36008 — High (CVSS 7.1): Frontier is Substrate's Ethereum compatibility layer. A security issue was discovered affecting parsing of the RPC…
- CVE-2022-21685 — Medium (CVSS 6.5): Frontier is Substrate's Ethereum compatibility layer. Prior to commit number…
- CVE-2022-39242 — Medium (CVSS 5.3): Frontier is an Ethereum compatibility layer for Substrate. Prior to commit d3beddc6911a559a3ecc9b3f08e153dbe37a8658,…
- CVE-2022-31111 — Medium (CVSS 5.3): Frontier is Substrate's Ethereum compatibility layer. In affected versions the truncation done when converting between…
- CVE-2021-41138 — Medium (CVSS 5.3): Frontier is Substrate's Ethereum compatibility layer. In the newly introduced signed Frontier-specific extrinsic for…
All CVEs affecting Parity Frontier →
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