How severe is CVE-2022-21685?

CVE-2022-21685 has a CVSS score of 6.5/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by CVE-2022-21685?

CVE-2022-21685 affects the following packages: pallet-evm-precompile-modexp (crates.io). Ecosystems affected: crates.io.

How do I fix CVE-2022-21685?

No patched version of pallet-evm-precompile-modexp has shipped for CVE-2022-21685 yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.

How do I detect CVE-2022-21685 in my crates.io dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for pallet-evm-precompile-modexp, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2022-21685 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Is CVE-2022-21685 actively exploited in the wild?

No public exploit code has been indexed for CVE-2022-21685 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2022-21685?

CVE-2022-21685 has an EPSS (Exploit Prediction Scoring System) score of 1.3%, placing it in the 70th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2022-21685?

CVE-2022-21685 is classified as CWE-191 (CWE-191). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2022-21685 published, and has it been updated?

CVE-2022-21685 was published on January 14, 2022 and was last updated on August 12, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🦀

🦀 crates.io

Not in CISA KEV

MEDIUM severity

CVE-2022-21685 — pallet-evm-precompile-mod…

MEDIUMFix: paritytech/frontier@8a93fdc

CVE-2022-21685 is a medium-severity (CVSS 6.5) CWE-191 vulnerability in pallet-evm-precompile-modexp. No vendor fix is recorded yet; mitigation options are listed below.

Integer underflow in Frontier

Also known asGHSA-cjg2-2fjg-fph4

Published

Jan 14, 2022

Updated

Aug 12, 2026

Affected

1 pkg

Patched

See advisory

Exploits

None indexed

Exploitation data as of Oct 4, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

1.3%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs70th percentile — riskier than 70% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

CVE-2022-21685 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 385,738 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.

Real-World Exposure

1 pkg affected

🦀pallet-evm-precompile-modexp

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects crates.io packages — download data is not available via public APIs for these ecosystems.

Description

Impact

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. It is recommended that you apply the patch as soon as possible.

If you do not use MODEXP precompile in your runtime, then you are not impacted.

Patches

Patches are applied in PR #549.

Workarounds

None.

References

Patch PR: #549

Credits

Thanks to SR-Labs for discovering the security vulnerability, and thanks to PureStake team for the patches.

For more information

If you have any questions or comments about this advisory:

Open an issue in the Frontier repo

Affected Packages

1 total

Ecosystem	Package	Vulnerable range	Fix
🦀crates.io	`pallet-evm-precompile-modexp`	all versions	No fix

Affected Products

1 product · 1 configurations

Application

frontierparity

≤ 2022-01-13

range

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for pallet-evm-precompile-modexp, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Remediation status
No patched version of pallet-evm-precompile-modexp has shipped for CVE-2022-21685 yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.
Mitigate without a patch
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Frequently Asked Questions

### Impact 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. It is recommended that you apply the patch as soon as possible. If you do not use MODEXP precompile in your runtime, then you are not impacted. ### Patches Patches are applied in PR #549. ### Workarounds None. ### References Patch PR: #549 ### Credits Thanks to SR-Labs for discovering the security

O3 Security · Impact-Aware SCA

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Find it across crates.io, including transitive dependencies.

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CVSS Score

6.5/10CVSS v3 base

Vector breakdown

Attack Vector

Network

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

Raw vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

CWE Classification

CWE-191CWE-191

Weaponization

No known public exploit tooling found.

Timeline

Disclosed

Jan 14, 2022

Last updated

Aug 12, 2026

Identifiers

CVE-2022-21685

GHSA-cjg2-2fjg-fph4

References

Advisorygithub.com Advisorygithub.com Advisorynvd.nist.gov Fixgithub.com Fixgithub.com Packagegithub.com

Related vulnerabilities

Also affects pallet-evm-precompile-modexp

This CVE is medium severity; 1 of 1 other CVE affecting pallet-evm-precompile-modexp is rated as high or higher (top: high).

CVE-2023-28431

Same weakness: CWE-191

This CVE is medium severity; 7 of 7 other CVEs with CWE-191 are rated as high or higher (top: critical).

GHSA-2vh6-hw4j-32wwCVE-2026-54754CVE-2026-54345CVE-2026-42326CVE-2026-46384CVE-2026-7736CVE-2026-34064Browse all CWE-191

Provenance

Sources

OSV.devNVDFIRST.org (EPSS)

Last verifiedAug 12, 2026

CVE-2022-21685 — pallet-evm-precompile-mod…

EPSS Exploitation Probability

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

Description

Impact

Patches

Workarounds

References

Credits

For more information

Affected Packages

Affected Products

Detection & mitigation playbook

Detect

Remediation status

Mitigate without a patch

Frequently Asked Questions

Is CVE-2022-21685 in your dependencies?