CVE-2020-36323

Severity: high (CVSS 8.2 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 2.0% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2021-04-14 · updated 2026-06-17
Weakness: CWE-134

Description

In the standard library in Rust before 1.52.0, there is an optimization for joining strings that can cause uninitialized bytes to be exposed (or the program to crash) if the borrowed string changes after its length is checked.

Affected products

Fedoraproject Fedora: 32, 33, 34
rust-lang rust: before 1.52.0 — fixed in 1.52.0

How to fix

Upgrade to a fixed version: rust-lang rust 1.52.0. Check the vendor advisory for mitigations.

References

https://github.com/rust-lang/rust/issues/80335
https://github.com/rust-lang/rust/pull/81728
https://github.com/rust-lang/rust/pull/81728#issuecomment-821549174
https://github.com/rust-lang/rust/pull/81728#issuecomment-824904190
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/CZ337CM4GFJLRDFVQCGC7J25V65JXOG5/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/TFUO3URYCO73D2Q4WYJBWAMJWGGVXQO4/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/VZG65GUW6Z2CYOQHF7T3TB5CZKIX6ZJE/
https://github.com/rust-lang/rust/issues/80335
https://github.com/rust-lang/rust/pull/81728
https://github.com/rust-lang/rust/pull/81728#issuecomment-821549174
https://github.com/rust-lang/rust/pull/81728#issuecomment-824904190
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/CZ337CM4GFJLRDFVQCGC7J25V65JXOG5/

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