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CVE-2021-29511

MEDIUM

Memory over-allocation in evm crate

Also known asGHSA-4jwq-572w-4388
Published
May 12, 2021
Updated
Mar 13, 2026
Affected
12 pkgs
Patched
12 / 12
Exploits
None indexed

EPSS Exploitation Probability

via FIRST.org ↗
1.3%probability of exploitation in next 30 days
Lower Risk66th percentile+0.90%
0.00%0.59%1.19%1.78%0.4%1.3%Dec 25Apr 26Jun 26

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Blast Radius

12 pkgs affected
🦀evm🦀evm-core🦀evm🦀evm🦀evm🦀evm🦀evm🦀evm-core+4 more

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

evm is a pure Rust implementation of Ethereum Virtual Machine. Prior to the patch, when executing specific EVM opcodes related to memory operations that use evm_core::Memory::copy_large, the evm crate can over-allocate memory when it is not needed, making it possible for an attacker to perform denial-of-service attack. The flaw was corrected in commit 19ade85. Users should upgrade to ==0.21.1, ==0.23.1, ==0.24.1, ==0.25.1, >=0.26.1. There are no workarounds. Please upgrade your evm crate version.

Affected Packages

12 total 12 fixed
EcosystemPackageVulnerable rangeFix
🦀crates.ioevmall versions0.21.1
🦀crates.ioevm-coreall versions0.21.1
🦀crates.ioevm0.22.0&&< 0.22.10.22.1
🦀crates.ioevm0.23.0&&< 0.23.10.23.1
🦀crates.ioevm0.24.0&&< 0.24.10.24.1
🦀crates.ioevm0.25.0&&< 0.25.10.25.1

Detection & mitigation playbook

Open-source dependency
  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for evm. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

  2. Fix

    Update evm to 0.21.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-29511 is resolved across your whole dependency graph.

  3. Workarounds

    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.

  4. How O3 protects you

    O3 pinpoints whether CVE-2021-29511 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to CVE-2021-29511. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

evm is a pure Rust implementation of Ethereum Virtual Machine. Prior to the patch, when executing specific EVM opcodes related to memory operations that use `evm_core::Memory::copy_large`, the `evm` crate can over-allocate memory when it is not needed, making it possible for an attacker to perform denial-of-service attack. The flaw was corrected in commit `19ade85`. Users should upgrade to `==0.21.1, ==0.23.1, ==0.24.1, ==0.25.1, >=0.26.1`. There are no workarounds. Please upgrade your `evm` crate version.
O3 Security · Impact-Aware SCA

Is CVE-2021-29511 in your dependencies?

O3 detects CVE-2021-29511 across crates.io dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.