CVE-2021-41116 [High] | Code Injection in Composer

Composer is an open source dependency manager for the PHP language. In affected versions windows users running Composer to install untrusted dependencies are subject to command injection and should upgrade their composer version. Other OSs and WSL are not affected. The issue has been resolved in composer versions 1.10.23 and 2.1.9. There are no workarounds for this issue.

#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2026-01-23	0.72%	0.97%	+0.26%
2	2025-11-21	1.89%	0.72%	-1.17%
3	2025-11-18	—	1.89%	—

Date

Old EPSS score

New EPSS score

Delta (New - Old)

2026-01-23

0.72%

0.97%

+0.26%

2025-11-21

1.89%

0.72%

-1.17%

2025-11-18

—

1.89%

—

Base score	Version	Severity	Vector	Exploitability	Impact	Score source
8.2	3.1	HIGH	`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:L/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: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:L) Attackers could change some data, but it’s limited—not everything goes. Availability (A:N) Service keeps running; no real outage angle.	2.8	4.7	[email protected]
9.8	3.1	CRITICAL	`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/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: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.	3.9	5.9	[email protected]
7.5	2.0	HIGH	`AV:N/AC:L/Au:N/C:P/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:P) Partial confidentiality impact. Integrity impact (I:P) Partial integrity impact. Availability impact (A:P) Partial availability impact.	10.0	6.4	[email protected]

Base score

Version

Severity

Vector

Exploitability

Impact

Score source

8.2

3.1

HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:L/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: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:L): Attackers could change some data, but it’s limited—not everything goes.
Availability (A:N): Service keeps running; no real outage angle.

2.8

4.7

[email protected]

9.8

3.1

CRITICAL

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/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: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.

3.9

5.9

[email protected]

7.5

2.0

HIGH

AV:N/AC:L/Au:N/C:P/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:P): Partial confidentiality impact.
Integrity impact (I:P): Partial integrity impact.
Availability impact (A:P): Partial availability impact.

10.0

6.4

[email protected]

OS Trackers for CVE-2021-41116

vendor	priority	summary	link
`alpine`	critical	CVE-2021-41116: 1 source package rows (composer); 9 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 2.	https://security.alpinelinux.org/vuln/CVE-2021-41116
`debian`	unimportant	CVE-2021-41116 unimportant priority: Debian including 1 source packages (composer), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5.	https://security-tracker.debian.org/tracker/CVE-2021-41116
`ubuntu`	negligible	CVE-2021-41116 negligible priority: Ubuntu including 1 source packages (composer), 15 status rows across 15 suites (bionic, focal, hirsute, impish, jammy, kinetic, lunar, mantic, noble, oracular, plucky, questing, trusty, upstream, xenial): not-affected 13, DNE 1, needed 1.	https://ubuntu.com/security/CVE-2021-41116

Affected software / configurations for CVE-2021-41116

Vendor	Product	Version	Raw CPE
getcomposer	composer	< 1.10.23	cpe:2.3:a:getcomposer:composer::::::::
getcomposer	composer	>= 2.0.0, < 2.1.9	cpe:2.3:a:getcomposer:composer::::::::
tenable	tenable.sc	< 5.21.0	cpe:2.3:a:tenable:tenable.sc::::::::

References for CVE-2021-41116

URL	Tags
https://github.com/composer/composer/commit/ca5e2f8d505fd3bfac6f7c85b82f2740becbc0aa	Patch Third Party Advisory
https://github.com/composer/composer/security/advisories/GHSA-frqg-7g38-6gcf	Third Party Advisory
https://www.sonarsource.com/blog/securing-developer-tools-package-managers/

URL

CVE-2021-41116 | Command injection in composer on Windows

Exploit prediction scoring system (EPSS) score for CVE-2021-41116

Common vulnerability scoring system (CVSS) metrics for CVE-2021-41116

Weakness enumeration for CVE-2021-41116

GitHub Security Advisory for CVE-2021-41116

OS Trackers for CVE-2021-41116

Affected software / configurations for CVE-2021-41116

References for CVE-2021-41116