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HIGH

CVE-2021-26958

CVSS v3

8.8

HIGH

EPSS Score

1.6 %

exploit probability, as of 2026-09-25

CISA KEV

No

known exploited

Exploitation

—

SSVC status

Description

An issue was discovered in the xcb crate through 2021-02-04 for Rust. It has a soundness violation because transmutation to the wrong type can happen after xcb::base::cast_event uses std::mem::transmute to return a reference to an arbitrary type.

Technical details

Published
2021-02-09

Frequently asked questions

What is CVE-2021-26958?

An issue was discovered in the xcb crate through 2021-02-04 for Rust. It has a soundness violation because transmutation to the wrong type can happen after xcb::base::cast_event uses std::mem::transmute to return a reference to an arbitrary type.

Is CVE-2021-26958 actively exploited?

Active exploitation of CVE-2021-26958 has not been confirmed. Its EPSS score was 1.6% on 2026-09-25, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2021-26958?

CVE-2021-26958 has a CVSS v3 base score of 8.8 (HIGH severity).

Is CVE-2021-26958 affecting your environment?

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