Rust advisories / tokio-rustls
Vulnerability HighRUSTSEC-2020-0019 · tokio-rustls
RUSTSEC-2020-0019: tokio-rustls reads may cause excessive memory usage
Short answerA security vulnerability in the tokio-rustls crate: tokio-rustls reads may cause excessive memory usage. High severity (CVSS 7.5). Fixed in 0.12.3, 0.13.1: update to a fixed version.
| Crate | tokio-rustls |
|---|---|
| Type | Vulnerability (denial-of-service) |
| Affected versions | From 0.12.0 before 0.12.3; from 0.13.0 before 0.13.1. |
| Fixed in | 0.12.3, 0.13.1 |
| Severity | High, CVSS 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
| Published | 2020-05-19 |
| Last changed | 2023-11-08 |
| Also known as | CVE-2020-35875, GHSA-2jfv-g3fh-xq3v |
What to do
- See which version you have:
cargo tree -i tokio-rustls(it also shows which of your dependencies pulls it in). - Update within your version requirement:
cargo update -p tokio-rustls. If the fix is a newer major or minor than your requirement allows, raise it in Cargo.toml (for exampletokio-rustls = "0.13.1") or update the dependency that pulls it in. - Check again with
cargo audit, or paste your Cargo.lock into our Cargo.toml checker.
Details from the advisory
tokio-rustls does not call process_new_packets immediately after read, so the expected termination condition wants_read always returns true. As long as new incoming data arrives faster than it is processed and the reader does not return pending, data will be buffered.
This may cause DoS.
References
- Package: crates.io/crates/tokio-rustls
- Advisory: rustsec.org/advisories/RUSTSEC-2020-0019.html
- Web: github.com/tokio-rs/tls/pull/14
From the RustSec Advisory Database (CC0-1.0) via the OSV export, downloaded Oct 24, 2026. Severity score computed from the published CVSS vector.
Up next
Same cratetokio-rustls: security historyEvery advisory for this crate, and whether it is safe to use today.Read it next →Did this answer your question?