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.
CVE-2006-5178
This CVE was only ever scored under CVSS v2.0. NVD CVSS v2.0 base 6.2 — v2 rates that MEDIUM (v2 bands: LOW 0.0–3.9 / MEDIUM 4.0–6.9 / HIGH 7.0–10.0; v2 has no CRITICAL band). Vector AV:L/AC:H/Au:N/C:C/I:C/A:C. CVSS v2 is an older, coarser metric than v3.1/v4.0 (no Scope, no User Interaction, no Attack Requirements), so it is not directly comparable to a v3 or v4 score. NVD has never re-scored this record under v3. EPSS predicts 0.7% exploitation probability in the next 30 days, which is reflected in EG Risk but does not lift the v2 base. Confidence: LOW.
- Lower severity and no public exploit yet
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v2.0 (legacy)
- 6.2MEDIUMNVD never assigned a CVSS v3 rating to this CVE
- EG Score
- 6.2(low)
- EG Risk
- 58(Track)EG Risk 58/100SSVC: Track
EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).
How it’s computedSeverity62% × 45%Exploitation65% × 40%Automatability30% × 15%Action: Routine — remediate on your standard cadence. - EPSS PROB
- 1%
- EPSS %ILE
- 49%
- KEV
- Not listed
Published
October 10, 2006
Last Modified
April 23, 2026
References (30)
- cve@mitrehttp://lists.grok.org.uk/pipermail/full-disclosure/2006-October/049850.html
- cve@mitrehttp://secunia.com/advisories/22235
- cve@mitrehttp://secunia.com/advisories/22424
- cve@mitrehttp://securityreason.com/securityalert/1692
- cve@mitrehttp://securitytracker.com/id?1016977
- cve@mitrehttp://www.hardened-php.net/advisory_082006.132.html
- cve@mitrehttp://www.mandriva.com/security/advisories?name=MDKSA-2006:185
- cve@mitrehttp://www.neosecurityteam.net/index.php?action=advisories&id=26
- cve@mitrehttp://www.securityfocus.com/archive/1/447649/100/0/threaded
- cve@mitrehttp://www.securityfocus.com/archive/1/448020/100/0/threaded
- cve@mitrehttp://www.securityfocus.com/archive/1/448953/100/0/threaded
- cve@mitrehttp://www.securityfocus.com/bid/20326
- cve@mitrehttp://www.turbolinux.com/security/2006/TLSA-2006-38.txt
- cve@mitrehttp://www.vupen.com/english/advisories/2006/3901
- cve@mitrehttps://exchange.xforce.ibmcloud.com/vulnerabilities/29340
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 10× in last 7d / 31× in last 30d)
Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.
- 2026-07-26 13:30 UTCEG score recompute▲ 6.20
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- 2026-05-31 06:27 UTCEG score recompute
- 2026-05-31 06:27 UTCGHSA enrichment
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Publicly available exploits
(1 reference)Working exploit code is in the public domain (1 Exploit-DB entry). Defenders should treat patch urgency accordingly — public PoCs typically lead to mass-exploitation within 24-72 hours.
- Exploit-DBEDB-10557✓ verifiedFirst seen Dec 19, 2009
PHP 5.2.12/5.3.1 - 'symlink()' open_basedir Bypass
Open source ↗
Related CVEs(same CWE)
Frequently asked(4)
What is CVE-2006-5178?
When was CVE-2006-5178 disclosed?
Is CVE-2006-5178 actively exploited?
How do I remediate CVE-2006-5178?
Dependency Blast Radius
Explore the affected products and dependency analysis for CVE-2006-5178
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