How severe is CVE-2021-28877?

CVE-2021-28877 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2021-28877 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (69th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-28877?

CVE-2021-28877 affects Rust-lang Rust. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-28877?

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

When was CVE-2021-28877 published?

CVE-2021-28877 was published on 2021-04-11 and last updated on 2026-06-17.

CVE-2021-28877

CVE-2021-28877 is a high-severity vulnerability in Rust-lang Rust with a CVSS 3.x base score of 7.5. 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: High (CVSS 3.x base score 7.5)
CVSS v2: 5.0
EPSS exploit prediction: 1% (69th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-119
Affected product: Rust-lang Rust
Published: 2021-04-11
Last modified: 2026-06-17

Description

In the standard library in Rust before 1.51.0, the Zip implementation calls __iterator_get_unchecked() for the same index more than once when nested. This bug can lead to a memory safety violation due to an unmet safety requirement for the TrustedRandomAccess trait.

Frequently asked questions

What is CVE-2021-28877?: In the standard library in Rust before 1.51.0, the Zip implementation calls __iterator_get_unchecked() for the same index more than once when nested. This bug can lead to a memory safety violation due to an unmet safety requirement for the TrustedRandomAccess trait.
How severe is CVE-2021-28877?: CVE-2021-28877 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2021-28877 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (69th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-28877?: CVE-2021-28877 affects Rust-lang Rust. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-28877?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2021-28877 published?: CVE-2021-28877 was published on 2021-04-11 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:rust-lang:rust:*:*:*:*:*:*:*:*

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