How severe is CVE-2021-28878?

CVE-2021-28878 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-2021-28878 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (78th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-28878?

CVE-2021-28878 primarily affects Rust-lang Rust. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-28878?

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-2021-28878 published?

CVE-2021-28878 was published on 2021-04-11 and last updated on 2026-06-17.

CVE-2021-28878

CVE-2021-28878 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: 4.3
EPSS exploit prediction: 2% (78th 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 1.52.0, the Zip implementation calls __iterator_get_unchecked() more than once for the same index (under certain conditions) when next_back() and next() are used together. This bug could lead to a memory safety violation due to an unmet safety requirement for the TrustedRandomAccess trait.

Frequently asked questions

What is CVE-2021-28878?: In the standard library in Rust before 1.52.0, the Zip implementation calls __iterator_get_unchecked() more than once for the same index (under certain conditions) when next_back() and next() are used together. This bug could lead to a memory safety violation due to an unmet safety requirement for the TrustedRandomAccess trait.
How severe is CVE-2021-28878?: CVE-2021-28878 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-2021-28878 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (78th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-28878?: CVE-2021-28878 primarily affects Rust-lang Rust. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-28878?: 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-2021-28878 published?: CVE-2021-28878 was published on 2021-04-11 and last updated on 2026-06-17.

References

Affected products (4)

cpe:2.3:a:rust-lang:rust:*:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:32:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*

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