CVE-2018-20996
Double free in crossbeam
An issue was discovered in the crossbeam crate before 0.4.1 for Rust. There is a double free because of destructor mishandling.
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
- High
- Integrity
- High
- Availability
- High
Exploit likelihood
What each source reports
NVD Score used
An issue was discovered in the crossbeam crate before 0.4.1 for Rust. There is a double free because of destructor mishandling.
- Record
CVE-2018-20996- CVSS 3.0
- 9.8 Critical
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - CVSS 2.0
- 7.5 High
AV:N/AC:L/Au:N/C:P/I:P/A:P - Weakness
- CWE-415
- Updated
- 2026-11-02
CVE List No score
An issue was discovered in the crossbeam crate before 0.4.1 for Rust. There is a double free because of destructor mishandling.
- Record
CVE-2018-20996- Updated
- 2026-11-02
EUVDEUVD-2021-1671 No score
An issue was discovered in the crossbeam crate before 0.4.1 for Rust. There is a double free because of destructor mishandling.
- Record
EUVD-2021-1671- Updated
- 2026-11-03
GitHub AdvisoriesGHSA-c3cw-c387-pj65
Double free in crossbeam
Even if an element is popped from a queue, crossbeam would run its destructor inside the epoch-based garbage collector. This is a source of double frees.
The flaw was corrected by wrapping elements inside queues in a ManuallyDrop.
- Record
GHSA-c3cw-c387-pj65- CVSS 3.0
- 9.8 Critical
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-415
- Updated
- 2026-11-02
OSV
An issue was discovered in the crossbeam crate before 0.4.1 for Rust. There is a double free because of destructor mishandling.
- Record
CVE-2018-20996- CVSS 3.0
- 9.8 Critical
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Updated
- 2026-11-02
OSVGHSA-c3cw-c387-pj65
Double free in crossbeam
Even if an element is popped from a queue, crossbeam would run its destructor inside the epoch-based garbage collector. This is a source of double frees.
The flaw was corrected by wrapping elements inside queues in a ManuallyDrop.
- Record
GHSA-c3cw-c387-pj65- CVSS 3.0
- 9.8 Critical
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-415
- Updated
- 2026-11-02
OSVRUSTSEC-2018-0009
MsQueue and SegQueue suffer from double-free
Even if an element is popped from a queue, crossbeam would run its destructor inside the epoch-based garbage collector. This is a source of double frees.
The flaw was corrected by wrapping elements inside queues in a
ManuallyDrop.
Thanks to @c0gent for reporting the issue.
- Record
RUSTSEC-2018-0009- CVSS 3.0
- 9.8 Critical
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Updated
- 2026-11-02
OSVUBUNTU-CVE-2018-20996
An issue was discovered in the crossbeam crate before 0.4.1 for Rust. There is a double free because of destructor mishandling.
- Record
UBUNTU-CVE-2018-20996- CVSS 3.0
- 9.8 Critical
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
crossbeamcrates.io |
0.4.0 up to 0.4.1 | 0.4.1 |
rust-crossbeam-epochUbuntu:20.04:LTS |
All versions, plus listed versions 0.7.1-10.7.2-20.7.2-3 |
None known |
rust-crossbeam-epochUbuntu:22.04:LTS |
All versions, plus listed versions 0.8.2-10.8.2-2 |
None known |
rust-crossbeam-epochUbuntu:24.04:LTS |
All versions, plus listed versions 0.9.13-10.9.18-1 |
None known |
rust-crossbeam-epochUbuntu:25.10 |
All versions, plus listed versions 0.9.18-1 |
None known |
rust-crossbeam-epochUbuntu:26.10 |
All versions, plus listed versions 0.9.18-10.9.20-1 |
None known |
rust-crossbeam-epochUbuntu:26.04:LTS |
All versions, plus listed versions 0.9.18-1 |
None known |
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-2018-20996 is a critical vulnerability (CVSS 9.8) in Crossbeam Project Crossbeam, published December 9, 2018. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 1.74%, the 77th percentile. Fixed in crossbeam 0.4.1.
References
rustsec.org/advisories/RUSTSEC-2018-0009.html
nvd.nist.gov/vuln/detail/CVE-2018-20996
github.com/crossbeam-rs/crossbeam-epoch/issues/82
crates.io/crates/crossbeam
ubuntu.com/security/CVE-2018-20996
cve.org/CVERecord?id=CVE-2018-20996