How severe is CVE-2020-35899?

CVE-2020-35899 has a CVSS 3.x base score of 5.5, rated medium severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2020-35899 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (29th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-35899?

CVE-2020-35899 affects Actix Actix-service. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2020-35899?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2020-35899 published?

CVE-2020-35899 was published on 2020-12-31 and last updated on 2026-06-17.

CVE-2020-35899

CVE-2020-35899 is a medium-severity vulnerability in Actix Actix-service with a CVSS 3.x base score of 5.5. 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-416.

Key facts

Severity: Medium (CVSS 3.x base score 5.5)
CVSS v2: 2.1
EPSS exploit prediction: 0% (29th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-416
Affected product: Actix Actix-service
Published: 2020-12-31
Last modified: 2026-06-17

Description

An issue was discovered in the actix-service crate before 1.0.6 for Rust. The Cell implementation allows obtaining more than one mutable reference to the same data.

Frequently asked questions

What is CVE-2020-35899?: An issue was discovered in the actix-service crate before 1.0.6 for Rust. The Cell implementation allows obtaining more than one mutable reference to the same data.
How severe is CVE-2020-35899?: CVE-2020-35899 has a CVSS 3.x base score of 5.5, rated medium severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2020-35899 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (29th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-35899?: CVE-2020-35899 affects Actix Actix-service. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2020-35899?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2020-35899 published?: CVE-2020-35899 was published on 2020-12-31 and last updated on 2026-06-17.

References

https://rustsec.org/advisories/RUSTSEC-2020-0046.html

Affected products (1)

cpe:2.3:a:actix:actix-service:*:*:*:*:*:rust:*:*

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