CVE-2020-36208
Data races in conquer-once
An issue was discovered in the conquer-once crate before 0.3.2 for Rust. Thread crossing can occur for a non-Send but Sync type, leading to memory corruption.
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
- High
- Integrity
- High
- Availability
- High
Exploit likelihood
What each source reports
NVD Score used
An issue was discovered in the conquer-once crate before 0.3.2 for Rust. Thread crossing can occur for a non-Send but Sync type, leading to memory corruption.
- Record
CVE-2020-36208- CVSS 3.1
- 7.8 High
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H - CVSS 2.0
- 4.6 Medium
AV:L/AC:L/Au:N/C:P/I:P/A:P - Weakness
- CWE-662, CWE-787
- Updated
- 2026-11-02
CVE List No score
An issue was discovered in the conquer-once crate before 0.3.2 for Rust. Thread crossing can occur for a non-Send but Sync type, leading to memory corruption.
- Record
CVE-2020-36208- Updated
- 2026-11-02
EUVDEUVD-2021-1547 No score
An issue was discovered in the conquer-once crate before 0.3.2 for Rust. Thread crossing can occur for a non-Send but Sync type, leading to memory corruption.
- Record
EUVD-2021-1547- Updated
- 2026-11-03
GitHub AdvisoriesGHSA-3jc5-5hc5-33gj
Data races in conquer-once
Affected versions of conquer-once implements Sync for its OnceCell type without restricting it to Sendable types.
This allows non-Send but Sync types such as MutexGuard to be sent across threads leading to undefined behavior and memory corruption in concurrent programs.
The issue was fixed by adding a Send constraint to OnceCell.
- Record
GHSA-3jc5-5hc5-33gj- CVSS 3.1
- 7.8 High
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-662, CWE-787
- Updated
- 2026-11-02
OSV
An issue was discovered in the conquer-once crate before 0.3.2 for Rust. Thread crossing can occur for a non-Send but Sync type, leading to memory corruption.
- Record
CVE-2020-36208- CVSS 3.1
- 7.8 High
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H - Updated
- 2026-11-02
OSVGHSA-3jc5-5hc5-33gj
Data races in conquer-once
Affected versions of conquer-once implements Sync for its OnceCell type without restricting it to Sendable types.
This allows non-Send but Sync types such as MutexGuard to be sent across threads leading to undefined behavior and memory corruption in concurrent programs.
The issue was fixed by adding a Send constraint to OnceCell.
- Record
GHSA-3jc5-5hc5-33gj- CVSS 3.1
- 7.8 High
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-662, CWE-787
- Updated
- 2026-11-02
OSVRUSTSEC-2020-0101
conquer-once's OnceCell lacks Send bound for its Sync trait.
Affected versions of conquer-once implements Sync for its OnceCell type
without restricting it to Sendable types.
This allows non-Send but Sync types such as MutexGuard to be sent across
threads leading to undefined behavior and memory corruption in concurrent
programs.
The issue was fixed by adding a Send constraint to OnceCell.
- Record
RUSTSEC-2020-0101- CVSS 3.1
- 7.8 High
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H - Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
conquer-oncecrates.io |
before 0.3.2 | 0.3.2 |
conquer-oncecrates.io |
0.0.0-0 up to 0.3.2 | 0.3.2 |
History
| Recorded | Changed | Sources |
|---|---|---|
| facts | ||
| 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-2020-36208 is a high vulnerability (CVSS 7.8) in Conquer-once Project Conquer-once, published December 22, 2020. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.44%, the 38th percentile. Fixed in conquer-once 0.3.2.