CVE-2021-29511 | Memory over-allocation in evm crate

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.

Published: 2021-05-12 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-29511 is rated Moderate Risk (50.1/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 1.28%). Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2021-29511

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.38% 1.28% +0.90%
2 2025-03-17 0.14% 0.38% +0.24%
3 2023-03-07 — 0.14% —

Full EPSS history (7 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-29511

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
6.5 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 2.8 3.6 [email protected]
6.5 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 2.8 3.6 [email protected]
4.0 2.0 MEDIUM
AV:N/AC:L/Au:S/C:N/I:N/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:S)
A single authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:P)
Partial availability impact.
 8.0 2.9 [email protected]

Weakness enumeration for CVE-2021-29511

GitHub Security Advisory for CVE-2021-29511

GHSA-4jwq-572w-4388 · Severity: medium · Ecosystem: rust — Memory over-allocation in evm crate

Affected software / configurations for CVE-2021-29511

Vendor Product Version Raw CPE
evm_project evm <= 0.21.0 cpe:2.3:a:evm_project:evm:*:*:*:*:*:rust:*:*
evm_project evm 0.22.0 cpe:2.3:a:evm_project:evm:0.22.0:*:*:*:*:rust:*:*
evm_project evm 0.23.0 cpe:2.3:a:evm_project:evm:0.23.0:*:*:*:*:rust:*:*
evm_project evm 0.24.0 cpe:2.3:a:evm_project:evm:0.24.0:*:*:*:*:rust:*:*
evm_project evm 0.25.0 cpe:2.3:a:evm_project:evm:0.25.0:*:*:*:*:rust:*:*
evm_project evm 0.26.0 cpe:2.3:a:evm_project:evm:0.26.0:*:*:*:*:rust:*:*

References for CVE-2021-29511

cvelogic Threat Intelligence