Summary
enum_map macro can cause UB when Enum trait is incorrectly implemented
Affected versions of this crate did not properly check the length of an enum when using enum_map! macro, trusting user-provided length.
When the LENGTH in the Enum trait does not match the array length in the EnumArray trait, this can result in the initialization of the enum map with uninitialized types, which in turn can allow an attacker to execute arbitrary code.
This problem can only occur with a manual implementation of the Enum trait, it will never occur for enums that use #[derive(Enum)].
Example code that triggers this vulnerability looks like this:
enum E {
A,
B,
C,
}
impl Enum for E {
const LENGTH: usize = 2;
fn from_usize(value: usize) -> E {
match value {
0 => E::A,
1 => E::B,
2 => E::C,
_ => unimplemented!(),
}
}
fn into_usize(self) -> usize {
self as usize
}
}
impl<V> EnumArray<V> for E {
type Array = [V; 3];
}
let _map: EnumMap<E, String> = enum_map! { _ => "Hello, world!".into() };
The flaw was corrected in commit b824e23 by putting LENGTH property on sealed trait for macro to read.
Impact
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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Frequently Asked Questions
- What is GHSA-RXHX-9FJ6-6H2M? GHSA-RXHX-9FJ6-6H2M is a high-severity security vulnerability in enum-map (rust), affecting versions >= 2.0.0-2, < 2.0.2. It is fixed in 2.0.2.
- Which versions of enum-map are affected by GHSA-RXHX-9FJ6-6H2M? enum-map (rust) versions >= 2.0.0-2, < 2.0.2 is affected.
- Is there a fix for GHSA-RXHX-9FJ6-6H2M? Yes. GHSA-RXHX-9FJ6-6H2M is fixed in 2.0.2. Upgrade to this version or later.
- Is GHSA-RXHX-9FJ6-6H2M exploitable, and should I be worried? Whether GHSA-RXHX-9FJ6-6H2M is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether GHSA-RXHX-9FJ6-6H2M is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix GHSA-RXHX-9FJ6-6H2M? Upgrade
enum-mapto 2.0.2 or later.