CVE-2018-20834

Exp

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).

Published: 2019-04-30 Last update: 2026-02-04 Assigner: [email protected] Source: [email protected]

Conclusion & alert: CVE-2018-20834 is rated High Exploit Risk (77.6/100): CVSS High severity, with medium exploitation likelihood (EPSS 3.15%). Core evidence: 1 public exploit reference(s) are indexed (Exploit-DB). EPSS rose +2.40% over the last day, indicating growing attacker interest. Mandatory action: Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Public exploit references (Exploit-DB) for CVE-2018-20834

EDB-ID Source Kind Published Link
nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2018-20834

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.75% 3.15% +2.40%
2 2026-02-13 0.77% 0.75% -0.02%
3 2026-01-28 0.77%

Full EPSS history (14 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2018-20834

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.5 3.0 HIGH
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:N)
Service keeps running; no real outage angle.
3.9 3.6 [email protected]
6.4 2.0 MEDIUM
AV:N/AC:L/Au:N/C:N/I:P/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:P)
Partial availability impact.
10.0 4.9 [email protected]

Weakness enumeration for CVE-2018-20834

GitHub Security Advisory for CVE-2018-20834

OS Trackers for CVE-2018-20834

vendor priority summary link
alpine CVE-2018-20834: 1 source package rows (tar); 33 state rows across 6 repos (3.19-main, 3.20-main, 3.21-main, 3.22-main, 3.23-main, edge-main); fixed 33, open 0. https://security.alpinelinux.org/vuln/CVE-2018-20834
debian not yet assigned CVE-2018-20834 not yet assigned priority: Debian including 1 source packages (node-tar), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2018-20834
redhat high https://access.redhat.com/security/cve/CVE-2018-20834
ubuntu medium CVE-2018-20834 medium priority: Ubuntu including 1 source packages (node-tar), 6 status rows across 6 suites (bionic, cosmic, disco, trusty, upstream, xenial): not-affected 5, released 1. https://ubuntu.com/security/CVE-2018-20834

Affected software / configurations for CVE-2018-20834

Vendor Product Version Raw CPE
isaacs tar < 2.2.2 cpe:2.3:a:isaacs:tar:*:*:*:*:*:*:*:*
isaacs tar >= 3.0.0, < 4.4.2 cpe:2.3:a:isaacs:tar:*:*:*:*:*:*:*:*

References for CVE-2018-20834

cvelogic Threat Intelligence