Remote Code Execution via web-accessible composer.phar
Composer is a dependency manager for PHP. Users publishing a composer.phar to a public web-accessible server where the composer.phar can be executed as a php file may be subject to a remote code execution vulnerability if PHP also has `register_argc_argv` enabled in php.ini. Versions 2.6.4, 2.2.22 and 1.10.27 patch this vulnerability. Users are advised to upgrade. Users unable to upgrade should make sure `register_argc_argv` is disabled in php.ini, and avoid publishing composer.phar to the web as this is not best practice.
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for the hundreds of thousands of vulnerabilities in the database; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for help- Published
- Sep 29, 2023
- Updated
- Jun 17, 2026
- EPSS
- 1.4% · 71th percentile
- CWE
- CWE-74
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Report tools
Action score
35
Monitor
Low priority for now.
- CVSS
- 35 / 40 · 8.8 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 1.4%
CISA SSVC decision
- Exploitation
- none
- Automatable
- no
- Technical impact
- total
Vulnrichment: CISA's decision-tree inputs.
CNA vs NVD score
- NVD
- 8.8
- CNA · GitHub_M
- 6.4
- 2.4 point gap
CVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:U/C:H/I:H/A:H
The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.
Affected systems
| Vendor | Product | CPE |
|---|---|---|
| getcomposer | composer | cpe:2.3:a:getcomposer:composer |
| debian | debian linux | cpe:2.3:o:debian:debian_linux |
| fedoraproject | fedora | cpe:2.3:o:fedoraproject:fedora |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- debian debian linux10.0
- fedoraproject fedora37
- fedoraproject fedora38
- getcomposer composerbefore 1.10.27
- getcomposer composer2.0.0 and later · before 2.2.21
- getcomposer composer2.3.0 and later · before 2.6.4
Versions reported by the vendor
Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.
composer composer
- 2.6.4, 2.2.21, 1.10.27, >= 2.0, < 2.2.22, < 1.10.27affected
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Debian:10 | composer | before 1.8.4-1+deb10u3 | 1.8.4-1+deb10u3 |
| Debian:12 | composer | before 2.5.5-1+deb12u4 | 2.5.5-1+deb12u4 |
| Debian:13 | composer | before 2.6.4-1 | 2.6.4-1 |
| openSUSE:Tumbleweed | php-composer2 | before 2.6.4-1.1 | 2.6.4-1.1 |
| Packagist | composer/composer | from 2.0.0 · before 2.2.22 | 2.2.22 |
| Packagist | composer/composer | from 2.3.0 · before 2.6.4 | 2.6.4 |
| Packagist | composer/composer | before 1.10.27 | 1.10.27 |
| SUSE:Linux Enterprise Module for Web and Scripting 15 SP4 | php-composer2 | before 2.2.3-150400.3.6.1 | 2.2.3-150400.3.6.1 |
| SUSE:Linux Enterprise Module for Web and Scripting 15 SP4 | php-composer2 | before 2.2.3-150400.3.6.1 | 2.2.3-150400.3.6.1 |
Same product
getcomposer: all recordsOther highest-scoring records for the same primary product.
- CVE-2021-41116Command injection in composer on Windows40Plan
- CVE-2026-40261Composer has Command Injection via Malicious Perforce Reference36Monitor
- CVE-2022-24828Missing input validation can lead to command execution in composer36Monitor
- CVE-2021-29472Missing argument delimiter can lead to code execution via VCS repository URLs or source download URLs on systems with Mercurial in composer36Monitor
- CVE-2015-8371Composer before 2016-02-10 allows cache poisoning from other projects built on the same host.35Monitor
- CVE-2026-40176Composer is vulnerable to Command Injection via Malicious Perforce Repository31Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| debian:composer | 2.5.5-1+deb12u4 · Debian:12 | Package registry (OSV) |
| opensuse:php-composer2 | 2.2.3-150400.3.6.1 · openSUSE:Leap 15.4 | Package registry (OSV) |
| Packagist:composer/composer | 1.10.27 | Package registry (OSV) |
| Packagist:composer/composer | 2.2.22 | Package registry (OSV) |
| Packagist:composer/composer | 2.6.4 | Package registry (OSV) |
| suse:php-composer2 | 2.2.3-150400.3.6.1 · SUSE:Linux Enterprise Module for Web and Scripting 15 SP4 | Package registry (OSV) |
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
No nightly-computed relations.
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
Attack conditions
- Anyone who can reach it over the internet can trigger it.
- A low-privileged account is enough.
- No user action is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- high · data can be read
- Integrity
- high · data or configuration can be modified
- Availability
- high · the service can be disrupted
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- High
- Integrity impact
- High
- Availability impact
- High
Weakness class (CWE)
CWE-74 · Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
nvd-primary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
Attack patterns (CAPEC)
- Buffer Overflow via Environment VariablesCAPEC-10likelihood: High · High
- Server Side Include (SSI) InjectionCAPEC-101likelihood: High · High
- HTTP Request SplittingCAPEC-105likelihood: Medium · High
- Command Line Execution through SQL InjectionCAPEC-108likelihood: Low · Very High
- Double EncodingCAPEC-120likelihood: Low · Medium
- Subverting Environment Variable ValuesCAPEC-13likelihood: High · Very High
- Format String InjectionCAPEC-135likelihood: High · High
- Client-side Injection-induced Buffer OverflowCAPEC-14likelihood: Medium · High
Change log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
- github.com/composer/composer/commit/4fce14795aba98e40b6c4f5047305aba17a6120d
- github.com/composer/composer/commit/955a48e6319c8962e5cd421b07c00ab3c728968c
- github.com/composer/composer/commit/95e091c921037b7b6564942845e7b738f6b95c9c
- github.com/composer/composer/security/advisories/GHSA-jm6m-4632-36hf
- lists.debian.org/debian-lts-announce/2024/03/msg00030.html
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/66H2WKFUO255T3BZTL72TNYJYH2XM5FG/
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/7AWYAUZNH565NWPIKGEIYBWHYNM5JGAE/
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/KFOPGPW2KS37O3KJWBRGTUWHTXCQXBS2/
Vendor advisories and official records. Exploit/PoC links are deliberately left out.