What is CVE-2006-5178?

CVE-2006-5178 is a vulnerability in PHP, classified under Concurrent Execution using Shared Resource with Improper Synchronization (Race Condition). Published 2006-10-10.

Is CVE-2006-5178 known to be exploited?

2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

Vulnerability in PHP

CVE-2006-5178

Race condition in the symlink function in PHP 5.1.6 and earlier allows local users to bypass the open_basedir restriction by using a combination of symlink, mkdir, and unlink functions to change the file path after the open_basedir check and before the file is opened by the underlying system, as demonstrated by symlinking a symlink into a subdirectory, to point to a parent directory via .. (dot dot) sequences, and then unlinking the resulting symlink.

Vulnerability class: Race Condition

Published 2006-10-10 · last modified 2026-06-16.

CVSS v2 metric

CVSS v2 base score 6.2 (Medium). Vector: AV:L/AC:H/Au:N/C:C/I:C/A:C. This CVE predates CVSS v3 and has no v3 score from NVD.

EPSS exploit prediction

EPSS: 0.007 (49.5th percentile), scored 2026-09-29.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 50th percentile — 49.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.007 · newest: 0.007 · change: -0.000

Affected products

PHP — versions 4.0, 4.0.1, 4.0.2

Weakness classification (CWE)

CWE-362 — Concurrent Execution using Shared Resource with Improper Synchronization (Race Condition)

Public proof-of-concept exploits

References

lists.grok.org.uk/pipermail/full-disclosure/2006-October/049850.html (mailing-list, Exploit)
www.securityfocus.com/archive/1/448953/100/0/threaded (vendor-advisory)
www.securityfocus.com/archive/1/447649/100/0/threaded (mailing-list)
www.turbolinux.com/security/2006/TLSA-2006-38.txt (vendor-advisory)
www.securityfocus.com/bid/20326 (Exploit, vdb-entry)
securityreason.com/securityalert/1692 (third-party-advisory)
www.neosecurityteam.net/index.php
secunia.com/advisories/22235 (Exploit, Vendor Advisory, third-party-advisory)
www.securityfocus.com/archive/1/448020/100/0/threaded (mailing-list)
www.vupen.com/english/advisories/2006/3901 (vdb-entry)

Frequently asked questions

What is CVE-2006-5178?: CVE-2006-5178 is a vulnerability in PHP, classified under Concurrent Execution using Shared Resource with Improper Synchronization (Race Condition). Published 2006-10-10.
Is CVE-2006-5178 known to be exploited?: 2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.