CVE-2021-41089 | `docker cp` allows unexpected chmod of host files

Moby is an open-source project created by Docker to enable software containerization. A bug was found in Moby (Docker Engine) where attempting to copy files using `docker cp` into a specially-crafted container can result in Unix file permission changes for existing files in the host’s filesystem, widening access to others. This bug does not directly allow files to be read, modified, or executed without an additional cooperating process. This bug has been fixed in Moby (Docker Engine) 20.10.9. Users should update to this version as soon as possible. Running containers do not need to be restarted.

Published: 2021-10-04 Last update: 2026-06-17 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-41089 is rated Low Risk (17.9/100): CVSS Low severity, with low exploitation likelihood (EPSS 0.27%). Low composite risk—no urgent action required; patch on your normal maintenance cycle and revisit priority if CVSS or EPSS increases.

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

Exploit prediction scoring system (EPSS) score for CVE-2021-41089

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 0.03% 0.27% +0.24%
2 2025-11-21 0.07% 0.03% -0.04%
3 2025-11-18 — 0.07% —

Full EPSS history (12 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-41089

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
2.8 3.1 LOW
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:L/I:N/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:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.
 1.1 1.4 [email protected]
6.3 3.1 MEDIUM
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:L 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:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:L)
Might cause slowdowns, glitches, or partial disruption—not a full brick.
 2.0 3.7 [email protected]
4.4 2.0 MEDIUM
AV:L/AC:M/Au:N/C:P/I:P/A:P Click to expand
Access vector (AV:L)
Requires local access to the target system.
Access complexity (AC:M)
Exploitation needs some favorable conditions, but not exceptional ones.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:P)
Partial availability impact.
 3.4 6.4 [email protected]

Weakness enumeration for CVE-2021-41089

GitHub Security Advisory for CVE-2021-41089

GHSA-v994-f8vw-g7j4 · Severity: low · Ecosystem: go — `docker cp` allows unexpected chmod of host files in Moby Docker Engine

OS Trackers for CVE-2021-41089

vendor priority summary link
alpine medium CVE-2021-41089: 1 source package rows (docker); 7 state rows across 7 repos (3.17-community, 3.18-community, 3.19-community, 3.20-community, 3.21-community, 3.22-community, edge-community); fixed 7, open 0. https://security.alpinelinux.org/vuln/CVE-2021-41089
debian not yet assigned CVE-2021-41089 not yet assigned priority: Debian including 1 source packages (docker.io), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2021-41089
gentoo low CVE-2021-41089: 1 GLSA(s) (202409-29), 1 atom(s) (app-containers/docker); latest impact low. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2021-41089
redhat medium — https://access.redhat.com/security/cve/CVE-2021-41089
suse medium CVE-2021-41089 severity moderate: SUSE including 296 source package names (2.0.2-4.2.20:runc-1.0.2-23.1, amazon/suse-sles-15-sp1-chost-byos-v20210304-hvm-ssd-x86_64, …), 1244 product×package rows across 327 product lines (Container rancher/elemental-teal-iso/5.4, Container rancher/elemental-teal-rt/5.4, … (327 product lines)): Fixed 1069, Known Affected 175. https://www.suse.com/security/cve/CVE-2021-41089/
ubuntu medium CVE-2021-41089 medium priority: Ubuntu including 1 source packages (docker.io), 8 status rows across 8 suites (bionic, focal, hirsute, impish, jammy, trusty, upstream, xenial): released 7, DNE 1. https://ubuntu.com/security/CVE-2021-41089

Affected software / configurations for CVE-2021-41089

Vendor Product Version Raw CPE
mobyproject moby < 20.10.9 cpe:2.3:a:mobyproject:moby:*:*:*:*:*:*:*:*
fedoraproject fedora 34 cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*
fedoraproject fedora 35 cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:*

References for CVE-2021-41089

cvelogic Threat Intelligence