CVE-2020-35904
Incorrect buffer size in crossbeam-channel
An issue was discovered in the crossbeam-channel crate before 0.4.4 for Rust. It has incorrect expectations about the relationship between the memory allocation and how many iterator elements there are.
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 crossbeam-channel crate before 0.4.4 for Rust. It has incorrect expectations about the relationship between the memory allocation and how many iterator elements there are.
- Record
CVE-2020-35904- 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 - Updated
- 2026-11-02
CVE List No score
An issue was discovered in the crossbeam-channel crate before 0.4.4 for Rust. It has incorrect expectations about the relationship between the memory allocation and how many iterator elements there are.
- Record
CVE-2020-35904- Updated
- 2026-11-02
EUVDEUVD-2021-1794 No score
An issue was discovered in the crossbeam-channel crate before 0.4.4 for Rust. It has incorrect expectations about the relationship between the memory allocation and how many iterator elements there are.
- Record
EUVD-2021-1794- Updated
- 2026-11-03
GitHub AdvisoriesGHSA-m8h8-v6jh-c762
Incorrect buffer size in crossbeam-channel
The affected version of this crate's the bounded channel incorrectly assumes that Vec::from_iter has allocated capacity that same as the number of iterator elements. Vec::from_iter does not actually guarantee that and may allocate extra memory. The destructor of the bounded channel reconstructs Vec from the raw pointer based on the incorrect assumes described above. This is unsound and causing deallocation with the incorrect capacity when Vec::from_iter has allocated different sizes with the number of iterator elements.
- Record
GHSA-m8h8-v6jh-c762- 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-131
- Updated
- 2026-11-02
OSVCVE-2020-15254
Crossbeam is a set of tools for concurrent programming. In crossbeam-channel before version 0.4.4, the bounded channel incorrectly assumes that Vec::from_iter has allocated capacity that same as the number of iterator elements. Vec::from_iter does not actually guarantee that and may allocate extra memory. The destructor of the bounded channel reconstructs Vec from the raw pointer based on the incorrect assumes described above. This is unsound and causing deallocation with the incorrect capacity when Vec::from_iter has allocated different sizes with the number of iterator elements. This has been fixed in crossbeam-channel 0.4.4.
- Record
CVE-2020-15254- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Updated
- 2026-11-02
OSV
An issue was discovered in the crossbeam-channel crate before 0.4.4 for Rust. It has incorrect expectations about the relationship between the memory allocation and how many iterator elements there are.
- Record
CVE-2020-35904- 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
Show 5 moreShow less
OSVDEBIAN-CVE-2020-35904
An issue was discovered in the crossbeam-channel crate before 0.4.4 for Rust. It has incorrect expectations about the relationship between the memory allocation and how many iterator elements there are.
- Record
DEBIAN-CVE-2020-35904- 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
OSVGHSA-m8h8-v6jh-c762
Incorrect buffer size in crossbeam-channel
The affected version of this crate's the bounded channel incorrectly assumes that Vec::from_iter has allocated capacity that same as the number of iterator elements. Vec::from_iter does not actually guarantee that and may allocate extra memory. The destructor of the bounded channel reconstructs Vec from the raw pointer based on the incorrect assumes described above. This is unsound and causing deallocation with the incorrect capacity when Vec::from_iter has allocated different sizes with the number of iterator elements.
- Record
GHSA-m8h8-v6jh-c762- 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-131
- Updated
- 2026-11-02
OSVGHSA-v5m7-53cv-f3hx
crossbeam-channel Undefined Behavior before v0.4.4
Impact
The affected version of this crate's the bounded channel incorrectly assumes that Vec::from_iter has allocated capacity that same as the number of iterator elements. Vec::from_iter does not actually guarantee that and may allocate extra memory. The destructor of the bounded channel reconstructs Vec from the raw pointer based on the incorrect assumes described above. This is unsound and causing deallocation with the incorrect capacity when Vec::from_iter has allocated different sizes with the number of iterator elements.
Patches
This has been fixed in crossbeam-channel 0.4.4.
We recommend users to upgrade to 0.4.4.
References
See https://github.com/crossbeam-rs/crossbeam/pull/533, https://github.com/crossbeam-rs/crossbeam/issues/539, and https://github.com/RustSec/advisory-db/pull/425 for more details.
License
This advisory is in the public domain.
- Record
GHSA-v5m7-53cv-f3hx- CVSS 3.1
- 8.1 High
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-119, CWE-401
- Updated
- 2026-11-02
OSVUBUNTU-CVE-2020-35904
An issue was discovered in the crossbeam-channel crate before 0.4.4 for Rust. It has incorrect expectations about the relationship between the memory allocation and how many iterator elements there are.
- Record
UBUNTU-CVE-2020-35904- 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
OSVRUSTSEC-2020-0052 No score
Undefined Behavior in bounded channel
The affected version of this crate's the bounded channel incorrectly assumes that Vec::from_iter has allocated capacity that same as the number of iterator elements. Vec::from_iter does not actually guarantee that and may allocate extra memory. The destructor of the bounded channel reconstructs Vec from the raw pointer based on the incorrect assumes described above. This is unsound and causing deallocation with the incorrect capacity when Vec::from_iter has allocated different sizes with the number of iterator elements.
- Record
RUSTSEC-2020-0052- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
crossbeam-channelcrates.io |
0.4.3 up to 0.4.4 | 0.4.4 |
rust-crossbeam-channelDebian:12 |
before 0.4.4-1 | 0.4.4-1 |
rust-crossbeam-channelDebian:13 |
before 0.4.4-1 | 0.4.4-1 |
rust-crossbeam-channelDebian:14 |
before 0.4.4-1 | 0.4.4-1 |
crossbeam-channelcrates.io From an advisory covering 2 CVEs |
0.4.3 up to 0.4.4 | 0.4.4 |
rust-crossbeam-channelUbuntu:20.04:LTS |
All versions, plus listed versions 0.3.9-2 |
None known |
History
| Recorded | Changed | Sources |
|---|---|---|
| affected, 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-2020-35904 is a medium vulnerability (CVSS 5.5) in Crossbeam-channel Project Crossbeam-channel, published June 26, 2020. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.39%, the 33rd percentile. Fixed in crossbeam-channel 0.4.4.