CVE-2018-20834
Arbitrary File Overwrite in tar
CVE-2018-20834 is a high vulnerability (CVSS 7.5) in Isaacs Tar, published April 30, 2019. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 3.15%, the 87th percentile. Fixed in tar 2.2.2.
A vulnerability was found in node-tar before version 4.4.2 (excluding version 2.2.2). An Arbitrary File Overwrite issue exists when extracting a tarball containing a hardlink to a file that already exists on the system, in conjunction with a later plain file with the same name as the hardlink. This plain file content replaces the existing file content. A patch has been applied to node-tar v2.2.2).
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
7.5
A vulnerability was found in node-tar before version 4.4.2 (excluding version 2.2.2). An Arbitrary File Overwrite issue exists when extracting a tarball containing a hardlink to a file that already exists on the system, in conjunction with a later plain file with the same name as the hardlink. This plain file content replaces the existing file content. A patch has been applied to node-tar v2.2.2).
- Record
CVE-2018-20834- 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
A vulnerability was found in node-tar before version 4.4.2 (excluding version 2.2.2). An Arbitrary File Overwrite issue exists when extracting a tarball containing a hardlink to a file that already exists on the system, in conjunction with a later plain file with the same name as the hardlink. This plain file content replaces the existing file content. A patch has been applied to node-tar v2.2.2).
- Record
CVE-2018-20834- Updated
- 2026-11-02
EUVDEUVD-2019-0468 No score
A vulnerability was found in node-tar before version 4.4.2 (excluding version 2.2.2). An Arbitrary File Overwrite issue exists when extracting a tarball containing a hardlink to a file that already exists on the system, in conjunction with a later plain file with the same name as the hardlink. This plain file content replaces the existing file content. A patch has been applied to node-tar v2.2.2).
- Record
EUVD-2019-0468- Updated
- 2026-11-03
GitHub AdvisoriesGHSA-j44m-qm6p-hp7m
7.5
Arbitrary File Overwrite in tar
Versions of tar prior to 4.4.2 for 4.x and 2.2.2 for 2.x are vulnerable to Arbitrary File Overwrite. Extracting tarballs containing a hardlink to a file that already exists in the system, and a file that matches the hardlink will overwrite the system's file with the contents of the extracted file.
Recommendation
For tar 4.x, upgrade to version 4.4.2 or later. For tar 2.x, upgrade to version 2.2.2 or later.
- Record
GHSA-j44m-qm6p-hp7m- 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
7.5
A vulnerability was found in node-tar before version 4.4.2 (excluding version 2.2.2). An Arbitrary File Overwrite issue exists when extracting a tarball containing a hardlink to a file that already exists on the system, in conjunction with a later plain file with the same name as the hardlink. This plain file content replaces the existing file content. A patch has been applied to node-tar v2.2.2).
- Record
CVE-2018-20834- 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
OSVDEBIAN-CVE-2018-20834
7.5
A vulnerability was found in node-tar before version 4.4.2 (excluding version 2.2.2). An Arbitrary File Overwrite issue exists when extracting a tarball containing a hardlink to a file that already exists on the system, in conjunction with a later plain file with the same name as the hardlink. This plain file content replaces the existing file content. A patch has been applied to node-tar v2.2.2).
- Record
DEBIAN-CVE-2018-20834- 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
Show 4 moreShow less
OSVGHSA-j44m-qm6p-hp7m
7.5
Arbitrary File Overwrite in tar
Versions of tar prior to 4.4.2 for 4.x and 2.2.2 for 2.x are vulnerable to Arbitrary File Overwrite. Extracting tarballs containing a hardlink to a file that already exists in the system, and a file that matches the hardlink will overwrite the system's file with the contents of the extracted file.
Recommendation
For tar 4.x, upgrade to version 4.4.2 or later. For tar 2.x, upgrade to version 2.2.2 or later.
- Record
GHSA-j44m-qm6p-hp7m- 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
OSVRHSA-2019:1821
8.8
Red Hat Security Advisory: rh-nodejs8-nodejs security update
- Record
RHSA-2019:1821- CVSS 3.0
- 8.8 High
CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H - Updated
- 2026-11-02
OSVCLSA-2026-1773620217 No score
TuxCare security update for tar (4 CVEs)
TuxCare rebuilt tar to address 4 CVEs. Fixed in 1.0.3-tuxcare.1.
- Record
CLSA-2026-1773620217- Updated
- 2026-11-02
OSVCLSA-2026-1774484514 No score
TuxCare security update for tar (5 CVEs)
TuxCare rebuilt tar to address 5 CVEs. Fixed in 2.1.1-tuxcare.1.
- Record
CLSA-2026-1774484514- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
tarnpm |
before 2.2.2 | 2.2.2 |
tarnpm |
3.0.0 up to 4.4.2 | 4.4.2 |
tarTuxCare:npm |
1.0.3-tuxcare.0 up to 1.0.3-tuxcare.1, plus listed versions 1.0.3 |
1.0.3-tuxcare.1 |
tarTuxCare:npm |
2.1.1-tuxcare.0 up to 2.1.1-tuxcare.1, plus listed versions 2.1.1 |
2.1.1-tuxcare.1 |
node-tarDebian:12 |
before 4.4.4+ds1-2 | 4.4.4+ds1-2 |
node-tarDebian:13 |
before 4.4.4+ds1-2 | 4.4.4+ds1-2 |
node-tarDebian:14 |
before 4.4.4+ds1-2 | 4.4.4+ds1-2 |
rh-nodejs8-nodejsRed Hat:rhel_software_collections:3::el7 |
before 0:8.16.0-1.el7 | 0:8.16.0-1.el7 |
rh-nodejs8-nodejs-debuginfoRed Hat:rhel_software_collections:3::el7 |
before 0:8.16.0-1.el7 | 0:8.16.0-1.el7 |
rh-nodejs8-nodejs-develRed Hat:rhel_software_collections:3::el7 |
before 0:8.16.0-1.el7 | 0:8.16.0-1.el7 |
rh-nodejs8-nodejs-docsRed Hat:rhel_software_collections:3::el7 |
before 0:8.16.0-1.el7 | 0:8.16.0-1.el7 |
rh-nodejs8-npmRed Hat:rhel_software_collections:3::el7 |
before 0:6.4.1-8.16.0.1.el7 | 0:6.4.1-8.16.0.1.el7 |
History
| When | Changed | Sources |
|---|---|---|
| 2026-11-03 | aliases | EUVD |
| 2026-11-02 | created | CVE List, GitHub Advisories, NVD, OSV |
References
hackerone.com/reports/344595
github.com/npm/node-tar/commit/b0c58433c22f5e7fe8b1c76373f27e3f81dcd4c8
github.com/npm/node-tar/compare/58a8d43...a5f7779
access.redhat.com/errata/RHSA-2019:1821
nvd.nist.gov/vuln/detail/CVE-2018-20834
github.com/npm/node-tar/commit/7ecef07da6a9e72cc0c4d0c9c6a8e85b6b52395d
Show 30 moreShow less
github.com/npm/node-tar/commits/v2.2.2
github.com/advisories/GHSA-j44m-qm6p-hp7m
security-tracker.debian.org/tracker/CVE-2018-20834
github.com/isaacs/node-tar
access.redhat.com/security/updates/classification
bugzilla.redhat.com/show_bug.cgi?id=1660998
bugzilla.redhat.com/show_bug.cgi?id=1661002
bugzilla.redhat.com/show_bug.cgi?id=1661005
bugzilla.redhat.com/show_bug.cgi?id=1661010
bugzilla.redhat.com/show_bug.cgi?id=1690808
bugzilla.redhat.com/show_bug.cgi?id=1702338
security.access.redhat.com/data/csaf/v2/advisories/2019/rhsa-2019_1821.json
access.redhat.com/security/cve/CVE-2018-12116
cve.org/CVERecord?id=CVE-2018-12116
nvd.nist.gov/vuln/detail/CVE-2018-12116
access.redhat.com/security/cve/CVE-2018-12121
cve.org/CVERecord?id=CVE-2018-12121
nvd.nist.gov/vuln/detail/CVE-2018-12121
access.redhat.com/security/cve/CVE-2018-12122
cve.org/CVERecord?id=CVE-2018-12122
nvd.nist.gov/vuln/detail/CVE-2018-12122
access.redhat.com/security/cve/CVE-2018-12123
cve.org/CVERecord?id=CVE-2018-12123
nvd.nist.gov/vuln/detail/CVE-2018-12123
access.redhat.com/security/cve/CVE-2018-20834
cve.org/CVERecord?id=CVE-2018-20834
access.redhat.com/security/cve/CVE-2019-5737
cve.org/CVERecord?id=CVE-2019-5737
nvd.nist.gov/vuln/detail/CVE-2019-5737
nodejs.org/ja/blog/vulnerability/february-2019-security-releases