CVE-2021-32803 [High] | Path Traversal in Tar

The npm package "tar" (aka node-tar) before versions 6.1.2, 5.0.7, 4.4.15, and 3.2.3 has an arbitrary File Creation/Overwrite vulnerability via insufficient symlink protection. `node-tar` aims to guarantee that any file whose location would be modified by a symbolic link is not extracted. This is, in part, achieved by ensuring that extracted directories are not symlinks. Additionally, in order to prevent unnecessary `stat` calls to determine whether a given path is a directory, paths are cached when directories are created. This logic was insufficient when extracting tar files that contained both a directory and a symlink with the same name as the directory. This order of operations resulted in the directory being created and added to the `node-tar` directory cache. When a directory is present in the directory cache, subsequent calls to mkdir for that directory are skipped. However, this is also where `node-tar` checks for symlinks occur. By first creating a directory, and then replacing that directory with a symlink, it was thus possible to bypass `node-tar` symlink checks on directories, essentially allowing an untrusted tar file to symlink into an arbitrary location and subsequently extracting arbitrary files into that location, thus allowing arbitrary file creation and overwrite. This issue was addressed in releases 3.2.3, 4.4.15, 5.0.7 and 6.1.2.

#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2026-05-06	0.16%	0.12%	-0.04%
2	2026-03-15	0.15%	0.16%	+0.01%
3	2026-02-19	—	0.15%	—

Date

Old EPSS score

New EPSS score

Delta (New - Old)

2026-05-06

0.16%

0.12%

-0.04%

2026-03-15

0.15%

0.16%

+0.01%

2026-02-19

—

0.15%

—

Base score	Version	Severity	Vector	Exploitability	Impact	Score source
8.2	3.1	HIGH	`CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N` Click to expand Attack vector (AV:L) They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by. 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:R) A real person has to do something—click, install, enable—otherwise it doesn’t land. Scope (S:C) Breaking this can reach past the original component and bite other resources—bigger blast radius. Confidentiality (C:H) Serious risk that confidential data gets exposed in a big 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.	1.8	5.8	[email protected]
8.1	3.1	HIGH	`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:H` 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:R) A real person has to do something—click, install, enable—otherwise it doesn’t land. 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:H) Could take the service down hard or make it unusable for people who depend on it.	2.8	5.2	[email protected]
5.8	2.0	MEDIUM	`AV:N/AC:M/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:M) Exploitation needs some favorable conditions, but not exceptional ones. 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.	8.6	4.9	[email protected]

Base score

Version

Severity

Vector

Exploitability

Impact

Score source

8.2

3.1

HIGH

CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N Click to expand

Attack vector (AV:L): They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
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:R): A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:C): Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:H): Serious risk that confidential data gets exposed in a big 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.

1.8

5.8

[email protected]

8.1

3.1

HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:H 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:R): A real person has to do something—click, install, enable—otherwise it doesn’t land.
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:H): Could take the service down hard or make it unusable for people who depend on it.

2.8

5.2

[email protected]

5.8

2.0

MEDIUM

AV:N/AC:M/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:M): Exploitation needs some favorable conditions, but not exceptional ones.
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.

8.6

4.9

[email protected]

OS Trackers for CVE-2021-32803

vendor	priority	summary	link
`alpine`	high	CVE-2021-32803: 1 source package rows (tar); 38 state rows across 10 repos (3.11-main, 3.12-main, 3.17-main, 3.18-main, 3.19-main, 3.20-main, 3.21-main, 3.22-main, 3.23-main, edge-main); fixed 36, open 2.	https://security.alpinelinux.org/vuln/CVE-2021-32803
`debian`	not yet assigned	CVE-2021-32803 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-2021-32803
`redhat`	medium	—	https://access.redhat.com/security/cve/CVE-2021-32803
`suse`	high	CVE-2021-32803 severity important: SUSE including 61 source package names (12-11.15:nodejs12-12.22.10-4.29.3, 12-11.15:npm12-12.22.10-4.29.3, …), 387 product×package rows across 34 product lines (Container bci/nodejs, SUSE CaaS Platform 4.0, … (34 product lines)): Fixed 367, Known Not Affected 20.	https://www.suse.com/security/cve/CVE-2021-32803/
`ubuntu`	medium	CVE-2021-32803 medium priority: Ubuntu including 1 source packages (node-tar), 15 status rows across 15 suites (bionic, focal, hirsute, impish, jammy, kinetic, lunar, mantic, noble, oracular, plucky, questing, trusty, upstream, xenial): not-affected 11, released 2, ignored 1, needs-triage 1.	https://ubuntu.com/security/CVE-2021-32803

Affected software / configurations for CVE-2021-32803

Vendor	Product	Version	Raw CPE
tar_project	tar	< 3.2.3	cpe:2.3:a:tar_project:tar::::::node.js::*
tar_project	tar	>= 4.0.0, < 4.4.15	cpe:2.3:a:tar_project:tar::::::node.js::*
tar_project	tar	>= 5.0.0, < 5.0.7	cpe:2.3:a:tar_project:tar::::::node.js::*
tar_project	tar	>= 6.0.0, < 6.1.2	cpe:2.3:a:tar_project:tar::::::node.js::*
oracle	graalvm	20.3.3	cpe:2.3:a:oracle:graalvm:20.3.3::::enterprise:::
oracle	graalvm	21.2.0	cpe:2.3:a:oracle:graalvm:21.2.0::::enterprise:::
siemens	sinec_infrastructure_network_services	< 1.0.1.1	cpe:2.3:a:siemens:sinec_infrastructure_network_services::::::::

References for CVE-2021-32803

URL	Tags
https://cert-portal.siemens.com/productcert/pdf/ssa-389290.pdf	Patch Third Party Advisory
https://github.com/npm/node-tar/commit/9dbdeb6df8e9dbd96fa9e84341b9d74734be6c20	Patch Third Party Advisory
https://github.com/npm/node-tar/security/advisories/GHSA-r628-mhmh-qjhw	Mitigation Third Party Advisory
https://www.npmjs.com/advisories/1771	Mitigation Third Party Advisory
https://www.npmjs.com/package/tar	Product Third Party Advisory
https://www.oracle.com/security-alerts/cpuoct2021.html	Patch Third Party Advisory

URL

CVE-2021-32803 | Arbitrary File Creation/Overwrite via insufficient symlink protection due to directory cache poisoning

Exploit prediction scoring system (EPSS) score for CVE-2021-32803

Common vulnerability scoring system (CVSS) metrics for CVE-2021-32803

Weakness enumeration for CVE-2021-32803

GitHub Security Advisory for CVE-2021-32803

OS Trackers for CVE-2021-32803

Affected software / configurations for CVE-2021-32803

References for CVE-2021-32803