How severe is CVE-2022-21685?

CVE-2022-21685 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2022-21685 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (68th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2022-21685?

CVE-2022-21685 affects Parity Frontier. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2022-21685?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2022-21685 published?

CVE-2022-21685 was published on 2022-01-14 and last updated on 2026-06-17.

CVE-2022-21685

CVE-2022-21685 is a medium-severity vulnerability in Parity Frontier with a CVSS 3.x base score of 6.5. 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-191.

Key facts

Severity: Medium (CVSS 3.x base score 6.5)
CVSS v2: 4.0
EPSS exploit prediction: 1% (68th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-191
Affected product: Parity Frontier
Published: 2022-01-14
Last modified: 2026-06-17

Description

Frontier is Substrate's Ethereum compatibility layer. Prior to commit number `8a93fdc6c9f4eb1d2f2a11b7ff1d12d70bf5a664`, a bug in Frontier's MODEXP precompile implementation can cause an integer underflow in certain conditions. This will cause a node crash for debug builds. For release builds (and production WebAssembly binaries), the impact is limited as it can only cause a normal EVM out-of-gas. Users who do not use MODEXP precompile in their runtime are not impacted. A patch is available in pull request #549.

Frequently asked questions

What is CVE-2022-21685?: Frontier is Substrate's Ethereum compatibility layer. Prior to commit number `8a93fdc6c9f4eb1d2f2a11b7ff1d12d70bf5a664`, a bug in Frontier's MODEXP precompile implementation can cause an integer underflow in certain conditions. This will cause a node crash for debug builds. For release builds (and production WebAssembly binaries), the impact is limited as it can only cause a normal EVM out-of-gas. Users who do not use MODEXP precompile in their runtime are not impacted. A patch is available in pull request #549.
How severe is CVE-2022-21685?: CVE-2022-21685 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2022-21685 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (68th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2022-21685?: CVE-2022-21685 affects Parity Frontier. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2022-21685?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2022-21685 published?: CVE-2022-21685 was published on 2022-01-14 and last updated on 2026-06-17.

References

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-2023-28431 — High (CVSS 7.5): Frontier is an Ethereum compatibility layer for Substrate. Frontier's `modexp` precompile uses `num-bigint` crate under…
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