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CVE-2018-20834

Arbitrary File Overwrite in tar

7.5 HighFix available

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

3.15%Up 1.5 points since Apr 14, 2021
90%50%10%1%

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 HighCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
CVSS 2.0
6.4 MediumAV: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 HighCVSS: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 HighCVSS: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 HighCVSS: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 HighCVSS: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 HighCVSS: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

Affected packages
PackageAffectedFixed
tar
npm
before 2.2.2
2.2.2
tar
npm
3.0.0 up to 4.4.2
4.4.2
tar
TuxCare:npm
1.0.3-tuxcare.0 up to 1.0.3-tuxcare.1, plus listed versions
1.0.3
1.0.3-tuxcare.1
tar
TuxCare: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-tar
Debian:12
before 4.4.4+ds1-2
4.4.4+ds1-2
node-tar
Debian:13
before 4.4.4+ds1-2
4.4.4+ds1-2
node-tar
Debian:14
before 4.4.4+ds1-2
4.4.4+ds1-2
rh-nodejs8-nodejs
Red Hat:rhel_software_collections:3::el7
before 0:8.16.0-1.el7
0:8.16.0-1.el7
rh-nodejs8-nodejs-debuginfo
Red Hat:rhel_software_collections:3::el7
before 0:8.16.0-1.el7
0:8.16.0-1.el7
rh-nodejs8-nodejs-devel
Red Hat:rhel_software_collections:3::el7
before 0:8.16.0-1.el7
0:8.16.0-1.el7
rh-nodejs8-nodejs-docs
Red Hat:rhel_software_collections:3::el7
before 0:8.16.0-1.el7
0:8.16.0-1.el7
rh-nodejs8-npm
Red 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

History
WhenChangedSources
2026-11-03aliasesEUVD
2026-11-02createdCVE List, GitHub Advisories, NVD, OSV

References

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