CVE-2018-20990
Arbitrary file overwrite in tar-rs
An issue was discovered in the tar crate before 0.4.16 for Rust. Arbitrary file overwrite can occur via a symlink or hardlink in a TAR archive.
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
- None
- Integrity
- High
- Availability
- None
Exploit likelihood
What each source reports
NVD Score used
An issue was discovered in the tar crate before 0.4.16 for Rust. Arbitrary file overwrite can occur via a symlink or hardlink in a TAR archive.
- Record
CVE-2018-20990- CVSS 3.0
- 7.5 High
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N - CVSS 2.0
- 6.4 Medium
AV:N/AC:L/Au:N/C:N/I:P/A:P - Weakness
- CWE-59
- Updated
- 2026-11-02
CVE List No score
An issue was discovered in the tar crate before 0.4.16 for Rust. Arbitrary file overwrite can occur via a symlink or hardlink in a TAR archive.
- Record
CVE-2018-20990- Updated
- 2026-11-02
EUVDEUVD-2021-1502 No score
An issue was discovered in the tar crate before 0.4.16 for Rust. Arbitrary file overwrite can occur via a symlink or hardlink in a TAR archive.
- Record
EUVD-2021-1502- Updated
- 2026-11-03
GitHub AdvisoriesGHSA-2367-c296-3mp2
Arbitrary file overwrite in tar-rs
When unpacking a tarball with the unpack_in-family of functions it's intended that only files within the specified directory are able to be written. Tarballs with hard links or symlinks, however, can be used to overwrite any file on the filesystem. Tarballs can contain multiple entries for the same file. A tarball which first contains an entry for a hard link or symlink pointing to any file on the filesystem will have the link created, and then afterwards if the same file is listed in the tarball the hard link will be rewritten and any file can be rewritten on the filesystem.
- Record
GHSA-2367-c296-3mp2- CVSS 3.0
- 7.5 High
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N - Weakness
- CWE-59
- Updated
- 2026-11-02
OSV
An issue was discovered in the tar crate before 0.4.16 for Rust. Arbitrary file overwrite can occur via a symlink or hardlink in a TAR archive.
- Record
CVE-2018-20990- CVSS 3.0
- 7.5 High
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N - Updated
- 2026-11-02
OSVGHSA-2367-c296-3mp2
Arbitrary file overwrite in tar-rs
When unpacking a tarball with the unpack_in-family of functions it's intended that only files within the specified directory are able to be written. Tarballs with hard links or symlinks, however, can be used to overwrite any file on the filesystem. Tarballs can contain multiple entries for the same file. A tarball which first contains an entry for a hard link or symlink pointing to any file on the filesystem will have the link created, and then afterwards if the same file is listed in the tarball the hard link will be rewritten and any file can be rewritten on the filesystem.
- Record
GHSA-2367-c296-3mp2- CVSS 3.0
- 7.5 High
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N - Weakness
- CWE-59
- Updated
- 2026-11-02
OSVRUSTSEC-2018-0002
Links in archives can overwrite any existing file
When unpacking a tarball with the unpack_in-family of functions it's intended
that only files within the specified directory are able to be written. Tarballs
with hard links or symlinks, however, can be used to overwrite any file on the
filesystem.
Tarballs can contain multiple entries for the same file. A tarball which first contains an entry for a hard link or symlink pointing to any file on the filesystem will have the link created, and then afterwards if the same file is listed in the tarball the hard link will be rewritten and any file can be rewritten on the filesystem.
This has been fixed in https://github.com/alexcrichton/tar-rs/pull/156 and is
published as tar 0.4.16. Thanks to Max Justicz for discovering this and
emailing about the issue!
- Record
RUSTSEC-2018-0002- CVSS 3.0
- 7.5 High
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N - Updated
- 2026-11-02
OSVUBUNTU-CVE-2018-20990
An issue was discovered in the tar crate before 0.4.16 for Rust. Arbitrary file overwrite can occur via a symlink or hardlink in a TAR archive.
- Record
UBUNTU-CVE-2018-20990- CVSS 3.0
- 7.5 High
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N - Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
tarcrates.io |
before 0.4.16 | 0.4.16 |
tarcrates.io |
0.0.0-0 up to 0.4.16 | 0.4.16 |
rust-tarUbuntu:Pro:20.04:LTS |
All versions, plus listed versions 0.4.26-10.4.26-1ubuntu0.1 |
None known |
rust-tarUbuntu:Pro:22.04:LTS |
All versions, plus listed versions 0.4.26-10.4.37-10.4.37-30.4.37-3ubuntu0.1~esm10.4.37-3ubuntu0.10.4.37-3ubuntu0.1+esm1 |
None known |
rust-tarUbuntu:24.04:LTS |
All versions, plus listed versions 0.4.38-20.4.40-10.4.40-1ubuntu0.1 |
None known |
rust-tarUbuntu:25.10 |
All versions, plus listed versions 0.4.43-40.4.43-4ubuntu0.1 |
None known |
rust-tarUbuntu:26.10 |
All versions, plus listed versions 0.4.45-10.4.45-2 |
None known |
rust-tarUbuntu:26.04:LTS |
All versions, plus listed versions 0.4.43-40.4.44-10.4.45-1 |
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-2018-20990 is a high vulnerability (CVSS 7.5) in Tar Project Tar, published June 29, 2018. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 1.68%, the 76th percentile. Fixed in tar 0.4.16.
References
rustsec.org/advisories/RUSTSEC-2018-0002.html
nvd.nist.gov/vuln/detail/CVE-2018-20990
github.com/alexcrichton/tar-rs/pull/156
crates.io/crates/tar
ubuntu.com/security/CVE-2018-20990
cve.org/CVERecord?id=CVE-2018-20990