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Fencer Intel
critical 9.8

CVE-2015-6834 in the critical feed json

Multiple use-after-free vulnerabilities in PHP before 5.4.45, 5.5.x before 5.5.29, and 5.6.x before 5.6.13 allow remote attackers to execut…

published 2016-05-16 10 y ago modified 2026-06-17 4 mo ago also EUVD-2015-6770

cvss
9.8
version 3.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
46.8%
EPSS 46.8% chance of exploitation in 30 days, percentile 98%
public exploits
2
Exploit-DB

Summary

Multiple use-after-free vulnerabilities in PHP before 5.4.45, 5.5.x before 5.5.29, and 5.6.x before 5.6.13 allow remote attackers to execute arbitrary code via vectors related to (1) the Serializable interface, (2) the SplObjectStorage class, and (3) the SplDoublyLinkedList class, which are mishandled during unserialization.

Patch / fix

  • php5 Ubuntu 14.04 LTS 5.5.9+dfsg-1ubuntu4.13

ubuntu advisories UBUNTU-CVE-2015-6834

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • rh-php56-php RHEL 2 SOFTWARE_COLLECTIONS 5.6.5-8.el6
  • rh-php56-php RHEL 2 SOFTWARE_COLLECTIONS 5.6.5-8.el7
  • rh-php56-php-gd RHEL 2 SOFTWARE_COLLECTIONS 5.6.5-8.el6
  • rh-php56-php-gd RHEL 2 SOFTWARE_COLLECTIONS 5.6.5-8.el7
  • rh-php56-php-cli RHEL 2 SOFTWARE_COLLECTIONS 5.6.5-8.el6
  • rh-php56-php-cli RHEL 2 SOFTWARE_COLLECTIONS 5.6.5-8.el7
  • rh-php56-php-dba RHEL 2 SOFTWARE_COLLECTIONS 5.6.5-8.el6
  • rh-php56-php-dba RHEL 2 SOFTWARE_COLLECTIONS 5.6.5-8.el7

red hat advisories RHSA-2016:0457

  • php5 SLE Software Development Kit 12, SLE Module for Web and Scripting 12 5.5.14-36.1

suse advisories SUSE-SU-2015:1633-1

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-2015-6834 updated cvss 5.1

php: multiple unserialization use-after-free issues

  • Red Hat Enterprise Linux 7 php, php-gd, php-cli, php-dba, php-fpm, php-pdo, +18 more Red Hat Software Collections php54-php, php55-php, php54-php-gd, php55-php-gd, php54-php-cli, php54-php-dba, +44 more
    affected: no fix planned “Will not fix”
  • Red Hat Software Collections for Red Hat Enterprise Linux Server (v. 6) rh-php56-php 5.6.5-8.el6, rh-php56-php-gd 5.6.5-8.el6, rh-php56-php-cli 5.6.5-8.el6, rh-php56-php-dba 5.6.5-8.el6, rh-php56-php-dbg 5.6.5-8.el6, rh-php56-php-fpm 5.6.5-8.el6, +22 more Red Hat Software Collections for Red Hat Enterprise Linux Server (v. 7) rh-php56-php 5.6.5-8.el7, rh-php56-php-gd 5.6.5-8.el7, rh-php56-php-cli 5.6.5-8.el7, rh-php56-php-dba 5.6.5-8.el7, rh-php56-php-dbg 5.6.5-8.el7, rh-php56-php-fpm 5.6.5-8.el7, +20 more Red Hat Software Collections for Red Hat Enterprise Linux Server EUS (v. 6.6) rh-php56-php 5.6.5-8.el6, rh-php56-php-gd 5.6.5-8.el6, rh-php56-php-cli 5.6.5-8.el6, rh-php56-php-dba 5.6.5-8.el6, rh-php56-php-dbg 5.6.5-8.el6, rh-php56-php-fpm 5.6.5-8.el6, +22 more Red Hat Software Collections for Red Hat Enterprise Linux Server EUS (v. 6.7) rh-php56-php 5.6.5-8.el6, rh-php56-php-gd 5.6.5-8.el6, rh-php56-php-cli 5.6.5-8.el6, rh-php56-php-dba 5.6.5-8.el6, rh-php56-php-dbg 5.6.5-8.el6, rh-php56-php-fpm 5.6.5-8.el6, +22 more Red Hat Software Collections for Red Hat Enterprise Linux Server EUS (v. 7.1) rh-php56-php 5.6.5-8.el7, rh-php56-php-gd 5.6.5-8.el7, rh-php56-php-cli 5.6.5-8.el7, rh-php56-php-dba 5.6.5-8.el7, rh-php56-php-dbg 5.6.5-8.el7, rh-php56-php-fpm 5.6.5-8.el7, +20 more Red Hat Software Collections for Red Hat Enterprise Linux Server EUS (v. 7.2) rh-php56-php 5.6.5-8.el7, rh-php56-php-gd 5.6.5-8.el7, rh-php56-php-cli 5.6.5-8.el7, rh-php56-php-dba 5.6.5-8.el7, rh-php56-php-dbg 5.6.5-8.el7, rh-php56-php-fpm 5.6.5-8.el7, +20 more
    +2 more products
    Red Hat Software Collections for Red Hat Enterprise Linux Workstation (v. 6) rh-php56-php 5.6.5-8.el6, rh-php56-php-gd 5.6.5-8.el6, rh-php56-php-cli 5.6.5-8.el6, rh-php56-php-dba 5.6.5-8.el6, rh-php56-php-dbg 5.6.5-8.el6, rh-php56-php-fpm 5.6.5-8.el6, +22 more Red Hat Software Collections for Red Hat Enterprise Linux Workstation (v. 7) rh-php56-php 5.6.5-8.el7, rh-php56-php-gd 5.6.5-8.el7, rh-php56-php-cli 5.6.5-8.el7, rh-php56-php-dba 5.6.5-8.el7, rh-php56-php-dbg 5.6.5-8.el7, rh-php56-php-fpm 5.6.5-8.el7, +20 more
    fixed: vendor fix RHSA-2016:0457
  • Red Hat Enterprise Linux 5 php, php53 Red Hat Enterprise Linux 6 php, php-gd, php-cli, php-dba, php-fpm, php-pdo, +20 more
    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

Timeline

  1. First public exploit (EDB-38122)
  2. Published

Exploit prediction

46.80% chance of exploitation in the next 30 days, higher than 98% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • EDB-38122 PHP 5.4/5.5/5.6 - SplObjectStorage 'Unserialize()' Use-After-Free dos, 2015-09-09
  • EDB-38120 PHP 5.4/5.5/5.6 - SplDoublyLinkedList 'Unserialize()' Use-After-Free dos, 2015-09-09

CVSS scores

assigned by version score vector
NVD 3.0 9.8 CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 7.5 AV:N/AC:L/Au:N/C:P/I:P/A:P

Classification

Technology feeds

References

Sources

Fencer Intel 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.