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Fencer Vulns
high 7.0

CVE-2026-59948 json

Composer: Arbitrary file write outside vendor via malicious transitive package name

published 2026-07-08 4 mo ago modified 2026-07-27 3 mo ago also BIT-composer-2026-59948 , EUVD-2026-42362 , GHSA-499r-g7pc-vmp9

cvss
7.0
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.1%
EPSS 0.1% chance of exploitation in 30 days, percentile 3%
public exploits
0
none known

Summary

Composer is a dependency Manager for the PHP language. Prior to 2.2.29 and 2.10.2, a maliciously crafted package from an untrusted repository other than Packagist.org or Private Packagist can cause Composer to write attacker-controlled files outside the vendor directory and outside the project during install or update by using an invalid package name that is not correctly validated before dependency-resolution results are written or installed. This issue is fixed in versions 2.2.29 and 2.10.2.

Patch / fix

  • packagist composer/composer 2.2.29, 2.10.2
  • bitnami composer 2.2.29, 2.10.2
  • getcomposer composer 2.2.29, 2.10.2
  • composer Debian 14 2.10.2-1

debian advisories DEBIAN-CVE-2026-59948

  • php-composer2 SLES for SAP 15 SP5, SLES for SAP 15 SP4, SLES 15 SP5-LTSS +5 more 2.2.30-150400.3.24.1
  • php-composer2 SLES for SAP 15 SP5, SLES for SAP 15 SP4, SLES 15 SP5-LTSS +5 more 2.2.30-150400.3.21.1
  • php-composer2 SLES 16.0, SLES for SAP applications 16.0 2.8.9-160000.4.1
  • php-composer2 SLES for SAP 15 SP6, SLES 15 SP6-LTSS, SLE Module for Web and Scripting 15 SP7 2.6.4-150600.3.12.1

suse advisories SUSE-SU-2026:4589-1SUSE-SU-2026:4283-1SUSE-SU-2026:23116-1SUSE-SU-2026:23138-1SUSE-SU-2026:3105-1

  • php-composer2 openSUSE Leap 16.0 2.8.9-160000.4.1
  • php-composer2 openSUSE Tumbleweed 2.10.2-1.1

opensuse advisories openSUSE-SU-2026:21520-1openSUSE-SU-2026:11268-1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-59948 updated cvss 7.0

composer/composer: Composer: Arbitrary file write via crafted package name

  • Red Hat Hardened Images composer
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
total
Assessed
4 mo ago

Exploit prediction

0.14% chance of exploitation in the next 30 days, higher than 3% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 7.0 CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
GitHub 3.1 7.0 CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
OSV 3.1 7.0 CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H

Affected packages

ecosystem package affected fixed in
packagist composer/composer
>=2.3.0, <2.10.2
>=1.0.0, <2.2.29
2.10.2
2.2.29
bitnami composer
>=1.0.0, <2.2.29
>=2.3.0, <2.10.2
2.2.29
2.10.2

Affected products

  • composer composer

Classification

Weakness
  • CWE-22 Improper Limitation of a Pathname to a Restricted Directory
  • CWE-787 Out-of-bounds Write

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.