How severe is CVE-2020-35917?

CVE-2020-35917 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-2020-35917 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (31st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-35917?

CVE-2020-35917 affects Pyo3 Project Pyo3. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2020-35917?

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

When was CVE-2020-35917 published?

CVE-2020-35917 was published on 2020-12-31 and last updated on 2026-06-17.

CVE-2020-35917

CVE-2020-35917 is a medium-severity vulnerability in Pyo3 Project Pyo3 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% (31st percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-416
Affected product: Pyo3 Project Pyo3
Published: 2020-12-31
Last modified: 2026-06-17

Description

An issue was discovered in the pyo3 crate before 0.12.4 for Rust. There is a reference-counting error and use-after-free in From<Py<T>>.

Frequently asked questions

What is CVE-2020-35917?: An issue was discovered in the pyo3 crate before 0.12.4 for Rust. There is a reference-counting error and use-after-free in From<Py<T>>.
How severe is CVE-2020-35917?: CVE-2020-35917 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-2020-35917 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (31st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-35917?: CVE-2020-35917 affects Pyo3 Project Pyo3. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2020-35917?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2020-35917 published?: CVE-2020-35917 was published on 2020-12-31 and last updated on 2026-06-17.

References

https://rustsec.org/advisories/RUSTSEC-2020-0074.html

Affected products (1)

cpe:2.3:a:pyo3_project:pyo3:*:*:*:*:*:rust:*:*

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