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CVE-2015-8371

25
FAUCET Score

CVE-2015-8371 describes a cache poisoning vulnerability in Composer versions prior to 2016-02-10, including 1.0.0-alpha11 and earlier, affecting server-side build processes. An attacker can inject malicious code by manipulating the dist package cache, which uses an easily guessable key, leading to arbitrary code execution. This vulnerability carries a CVSS v3.1 score of 8.8 (High) due to its network-based attack vector, low attack complexity, and high impact on confidentiality, integrity, and availability. There is no evidence of active exploitation, public exploit code (Metasploit, Nuclei, ExploitDB), or significant community discussion surrounding this CVE.

Impacted Technologies

VendorProductVersion(s)CPE
1.0.0CPE matchmatch criteria
cpe:2.3:a:getcomposer:composer:1.0.0:alpha1:*:*:*:*:*:*
1.0.0CPE matchmatch criteria
cpe:2.3:a:getcomposer:composer:1.0.0:alpha10:*:*:*:*:*:*
1.0.0CPE matchmatch criteria
cpe:2.3:a:getcomposer:composer:1.0.0:alpha11:*:*:*:*:*:*
1.0.0CPE matchmatch criteria
cpe:2.3:a:getcomposer:composer:1.0.0:alpha2:*:*:*:*:*:*
1.0.0CPE matchmatch criteria
cpe:2.3:a:getcomposer:composer:1.0.0:alpha3:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

8.8HIGH

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

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
REQUIRED
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
Exploitability Score
2.8
Impact Score
5.9
CvssVersion
3.1

Exploit Intelligence

EPSS Score
0.70%
Probability of exploitation in next 30 days
EPSS Percentile
49.2%
Percentile rank of EPSS score among Peer Group
As of 2026-07-25
Model: v2026.06.15
This CVE's current EPSS score of 0.0070 is in the 51st percentile among its peer group of 14,848 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.2 Bluesky, 0.1 Mastodon, and 0.2 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.3 InfoSec Media, 0.0 Vendor Blog, and 0.1 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (1)

composerpatch availablevia ghsa
Product: composer/composerFixed in: 1.0.0

Vendor Advisories (1)

composerGHSA-725m-w832-q973high

Composer allows cache poisoning from other projects built on the same host

Sep 21, 2023

References

flyingmana.de / blog_en/2016/02/14/composer_cache_injection_vulnerability_cve_2015_8371.html
ExploitThird Party Advisory
github.com / composer/composer
Product
github.com / FriendsOfPHP/security-advisories/blob/e26be423c5bcfdb38478d2f92d1f928c15afb561/composer/composer/CVE-2015-8371.yaml
Third Party Advisory
gitlab.com / gitlab-org/advisories-community/-/blob/main/packagist/composer/composer/CVE-2015-8371.yml
Third Party Advisory