How severe is CVE-2021-30454?

CVE-2021-30454 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2021-30454 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (62nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-30454?

CVE-2021-30454 affects Outer Cgi Project Outer Cgi. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-30454?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2021-30454 published?

CVE-2021-30454 was published on 2021-04-07 and last updated on 2026-06-17.

CVE-2021-30454

CVE-2021-30454 is a critical-severity vulnerability in Outer Cgi Project Outer Cgi with a CVSS 3.x base score of 9.8. 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-119.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 7.5
EPSS exploit prediction: 1% (62nd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-119
Affected product: Outer Cgi Project Outer Cgi
Published: 2021-04-07
Last modified: 2026-06-17

Description

An issue was discovered in the outer_cgi crate before 0.2.1 for Rust. A user-provided Read instance receives an uninitialized memory buffer from KeyValueReader.

Frequently asked questions

What is CVE-2021-30454?: An issue was discovered in the outer_cgi crate before 0.2.1 for Rust. A user-provided Read instance receives an uninitialized memory buffer from KeyValueReader.
How severe is CVE-2021-30454?: CVE-2021-30454 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-30454 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (62nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-30454?: CVE-2021-30454 affects Outer Cgi Project Outer Cgi. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-30454?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2021-30454 published?: CVE-2021-30454 was published on 2021-04-07 and last updated on 2026-06-17.

References

https://rustsec.org/advisories/RUSTSEC-2021-0051.html

Affected products (1)

cpe:2.3:a:outer_cgi_project:outer_cgi:*:*:*:*:*:rust:*:*

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