CVE-2021-26308
Uninitialized buffer use in marc
An issue was discovered in the marc crate before 2.0.0 for Rust. A user-provided Read implementation can gain access to the old contents of newly allocated memory, violating soundness.
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
- None
- Availability
- None
Exploit likelihood
What each source reports
NVD Score used
An issue was discovered in the marc crate before 2.0.0 for Rust. A user-provided Read implementation can gain access to the old contents of newly allocated memory, violating soundness.
- Record
CVE-2021-26308- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N - CVSS 2.0
- 5.0 Medium
AV:N/AC:L/Au:N/C:P/I:N/A:N - Updated
- 2026-11-02
CVE List No score
An issue was discovered in the marc crate before 2.0.0 for Rust. A user-provided Read implementation can gain access to the old contents of newly allocated memory, violating soundness.
- Record
CVE-2021-26308- Updated
- 2026-11-02
EUVDEUVD-2021-1549 No score
An issue was discovered in the marc crate before 2.0.0 for Rust. A user-provided Read implementation can gain access to the old contents of newly allocated memory, violating soundness.
- Record
EUVD-2021-1549- Updated
- 2026-11-03
GitHub AdvisoriesGHSA-3mf3-2gv9-h39j
Uninitialized buffer use in marc
Affected versions of this crate passes an uninitialized buffer to a user-provided Read implementation. (Record::read()). Arbitrary Read implementations can read from the uninitialized buffer (memory exposure) and also can return incorrect number of bytes written to the buffer. Reading from uninitialized memory produces undefined values that can quickly invoke undefined behavior. This flaw was fixed in commit 6299af0 by zero-initializing the newly allocated memory (via data.resize(len, 0)) instead of exposing uninitialized memory (unsafe { data.set_len(len) }).
- Record
GHSA-3mf3-2gv9-h39j- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N - Weakness
- CWE-908
- Updated
- 2026-11-02
OSV
An issue was discovered in the marc crate before 2.0.0 for Rust. A user-provided Read implementation can gain access to the old contents of newly allocated memory, violating soundness.
- Record
CVE-2021-26308- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N - Updated
- 2026-11-02
OSVGHSA-3mf3-2gv9-h39j
Uninitialized buffer use in marc
Affected versions of this crate passes an uninitialized buffer to a user-provided Read implementation. (Record::read()). Arbitrary Read implementations can read from the uninitialized buffer (memory exposure) and also can return incorrect number of bytes written to the buffer. Reading from uninitialized memory produces undefined values that can quickly invoke undefined behavior. This flaw was fixed in commit 6299af0 by zero-initializing the newly allocated memory (via data.resize(len, 0)) instead of exposing uninitialized memory (unsafe { data.set_len(len) }).
- Record
GHSA-3mf3-2gv9-h39j- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N - Weakness
- CWE-908
- Updated
- 2026-11-02
OSVRUSTSEC-2021-0014
Record::read : Custom `Read` on uninitialized buffer may cause UB
Affected versions of this crate passes an uninitialized buffer to a user-provided Read implementation. (Record::read())
Arbitrary Read implementations can read from the uninitialized buffer (memory exposure) and also can return incorrect number of bytes written to the buffer.
Reading from uninitialized memory produces undefined values that can quickly invoke undefined behavior.
This flaw was fixed in commit 6299af0 by zero-initializing the newly allocated memory (via data.resize(len, 0)) instead of exposing uninitialized memory (unsafe { data.set_len(len) }).
- Record
RUSTSEC-2021-0014- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N - Updated
- 2026-11-02
Affected products
Affected packages
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-2021-26308 is a high vulnerability (CVSS 7.5) in Marc Project Marc, published January 26, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 1.52%, the 74th percentile. Fixed in marc 2.0.0.