CVE-2020-35875
Excessive memory usage in tokio-rustls
An issue was discovered in the tokio-rustls crate before 0.13.1 for Rust. Excessive memory usage may occur when data arrives quickly.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Exploit likelihood
What each source reports
NVD Score used
An issue was discovered in the tokio-rustls crate before 0.13.1 for Rust. Excessive memory usage may occur when data arrives quickly.
- Record
CVE-2020-35875- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - CVSS 2.0
- 5.0 Medium
AV:N/AC:L/Au:N/C:N/I:N/A:P - Updated
- 2026-11-02
CVE List No score
An issue was discovered in the tokio-rustls crate before 0.13.1 for Rust. Excessive memory usage may occur when data arrives quickly.
- Record
CVE-2020-35875- Updated
- 2026-11-02
EUVDEUVD-2021-1514 No score
An issue was discovered in the tokio-rustls crate before 0.13.1 for Rust. Excessive memory usage may occur when data arrives quickly.
- Record
EUVD-2021-1514- Updated
- 2026-11-03
GitHub AdvisoriesGHSA-2jfv-g3fh-xq3v
Excessive memory usage in tokio-rustls
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.
- Record
GHSA-2jfv-g3fh-xq3v- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-400
- Updated
- 2026-11-02
OSVGHSA-2jfv-g3fh-xq3v
Excessive memory usage in tokio-rustls
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.
- Record
GHSA-2jfv-g3fh-xq3v- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-400
- Updated
- 2026-11-02
OSVRUSTSEC-2020-0019
tokio-rustls reads may cause excessive memory usage
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.
- Record
RUSTSEC-2020-0019- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
tokio-rustlscrates.io |
0.12.0 up to 0.12.3 | 0.12.3 |
tokio-rustlscrates.io |
0.13.0 up to 0.13.1 | 0.13.1 |
tokio-rustlscrates.io |
0.12.0 up to 0.12.3, 0.13.0 up to 0.13.1 | 0.12.30.13.1 |
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2020-35875 is a high vulnerability (CVSS 7.5) in Tokio Tokio-rustls, published May 19, 2020. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 1.35%, the 71st percentile. Fixed in tokio-rustls 0.12.3.