CVE-2021-41103 | Insufficiently restricted permissions on plugin directories

containerd is an open source container runtime with an emphasis on simplicity, robustness and portability. A bug was found in containerd where container root directories and some plugins had insufficiently restricted permissions, allowing otherwise unprivileged Linux users to traverse directory contents and execute programs. When containers included executable programs with extended permission bits (such as setuid), unprivileged Linux users could discover and execute those programs. When the UID of an unprivileged Linux user on the host collided with the file owner or group inside a container, the unprivileged Linux user on the host could discover, read, and modify those files. This vulnerability has been fixed in containerd 1.4.11 and containerd 1.5.7. Users should update to these version when they are released and may restart containers or update directory permissions to mitigate the vulnerability. Users unable to update should limit access to the host to trusted users. Update directory permission on container bundles directories.

Published: 2021-10-04 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-41103 is rated Moderate Risk (48.2/100): CVSS High severity, with low exploitation likelihood (EPSS 0.25%). Review affected assets and schedule remediation.

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-2021-41103

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 2026-06-06 0.22% 0.25% +0.03%
2 2026-05-26 0.26% 0.22% -0.04%
3 2026-05-12 — 0.26% —

Full EPSS history (14 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-41103

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.8 3.1 HIGH
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H 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:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
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:H)
Could take the service down hard or make it unusable for people who depend on it.
 1.8 5.9 [email protected]
5.9 3.0 MEDIUM
CVSS:3.0/AV:L/AC:L/PR:N/UI:N/S:U/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: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: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.
 2.5 3.4 [email protected]
7.2 2.0 HIGH
AV:L/AC:L/Au:N/C:C/I:C/A:C Click to expand
Access vector (AV:L)
Requires local access to the target system.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:C)
Complete confidentiality impact.
Integrity impact (I:C)
Complete integrity impact.
Availability impact (A:C)
Complete availability impact.
 3.9 10.0 [email protected]

Weakness enumeration for CVE-2021-41103

GitHub Security Advisory for CVE-2021-41103

GHSA-c2h3-6mxw-7mvq · Severity: medium · Ecosystem: go — Insufficiently restricted permissions on plugin directories

OS Trackers for CVE-2021-41103

vendor priority summary link
alpine — CVE-2021-41103: 1 source package rows (containerd); 23 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 16. https://security.alpinelinux.org/vuln/CVE-2021-41103
debian not yet assigned CVE-2021-41103 not yet assigned priority: Debian including 1 source packages (containerd), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2021-41103
gentoo normal CVE-2021-41103: 1 GLSA(s) (202401-31), 1 atom(s) (app-containers/containerd); latest impact normal. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2021-41103
redhat medium — https://access.redhat.com/security/cve/CVE-2021-41103
suse medium CVE-2021-41103 severity moderate: SUSE including 299 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, …), 1248 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 1094, Known Affected 154. https://www.suse.com/security/cve/CVE-2021-41103/
ubuntu high CVE-2021-41103 high priority: Ubuntu including 1 source packages (containerd), 8 status rows across 8 suites (bionic, focal, hirsute, impish, jammy, trusty, upstream, xenial): released 7, DNE 1. https://ubuntu.com/security/CVE-2021-41103

Affected software / configurations for CVE-2021-41103

Vendor Product Version Raw CPE
linuxfoundation containerd < 1.4.11 cpe:2.3:a:linuxfoundation:containerd:*:*:*:*:*:*:*:*
linuxfoundation containerd >= 1.5.0, < 1.5.7 cpe:2.3:a:linuxfoundation:containerd:*:*:*:*:*:*:*:*
fedoraproject fedora 34 cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*
fedoraproject fedora 35 cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:*
debian debian_linux 11.0 cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:*

References for CVE-2021-41103

cvelogic Threat Intelligence