CVE-2020-35899
Use after free in actix-service
An issue was discovered in the actix-service crate before 1.0.6 for Rust. The Cell implementation allows obtaining more than one mutable reference to the same data.
Attack profile
How easy it is to exploit
- Attack vector
- Local
- Complexity
- Low
- Privileges needed
- Low
- 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 actix-service crate before 1.0.6 for Rust. The Cell implementation allows obtaining more than one mutable reference to the same data.
- Record
CVE-2020-35899- CVSS 3.1
- 5.5 Medium
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H - CVSS 2.0
- 2.1 Low
AV:L/AC:L/Au:N/C:N/I:N/A:P - Weakness
- CWE-416
- Updated
- 2026-11-02
CVE List No score
An issue was discovered in the actix-service crate before 1.0.6 for Rust. The Cell implementation allows obtaining more than one mutable reference to the same data.
- Record
CVE-2020-35899- Updated
- 2026-11-02
EUVDEUVD-2021-1917 No score
An issue was discovered in the actix-service crate before 1.0.6 for Rust. The Cell implementation allows obtaining more than one mutable reference to the same data.
- Record
EUVD-2021-1917- Updated
- 2026-11-03
GitHub AdvisoriesGHSA-whc7-5p35-4ww2
Use after free in actix-service
An issue was discovered in the actix-service crate before 1.0.6 for Rust. The Cell implementation allows obtaining more than one mutable reference to the same data.
- Record
GHSA-whc7-5p35-4ww2- CVSS 3.1
- 5.5 Medium
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-416
- Updated
- 2026-11-02
OSVGHSA-whc7-5p35-4ww2
Use after free in actix-service
An issue was discovered in the actix-service crate before 1.0.6 for Rust. The Cell implementation allows obtaining more than one mutable reference to the same data.
- Record
GHSA-whc7-5p35-4ww2- CVSS 3.1
- 5.5 Medium
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-416
- Updated
- 2026-11-02
OSVRUSTSEC-2020-0046
bespoke Cell implementation allows obtaining several mutable references to the same data
The custom implementation of a Cell primitive in the affected versions of this crate does not keep track of mutable references to the underlying data.
This allows obtaining several mutable references to the same object which may result in arbitrary memory corruption, most likely use-after-free.
The flaw was corrected by switching from a bespoke Cell<T> implementation to Rc<RefCell<T>>.
- Record
RUSTSEC-2020-0046- CVSS 3.1
- 5.5 Medium
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
actix-servicecrates.io |
before 1.0.6 | 1.0.6 |
actix-servicecrates.io |
0.0.0-0 up to 1.0.6 | 1.0.6 |
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-2020-35899 is a medium vulnerability (CVSS 5.5) in Actix Actix-service, published January 8, 2020. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.38%, the 32nd percentile. Fixed in actix-service 1.0.6.