CVE-2017-17671

Name: CVE-2017-17671
Creator: NVD / NIST
Published: 2017-12-14T00:29:00.217+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

CRITICALCVSS 9.8/10EPSS 3.05%

Last modified Jun 17, 2026

CVE-2017-17671 is a critical-severity vulnerability rated 9.8/10 on the CVSS scale. vBulletin through 5.3.x on Windows allows remote PHP code execution because a require_once call is reachable with an unauthenticated request that can include directory traversal sequences to specify an arbitrary pathname, and because ../ traversal is blocked but ..\ traversal is not blocked. For example, an attacker can make an invalid HTTP request containing PHP code, and then make an index.php?routestring= request with enough instances of ".." to reach an Apache HTTP Server log file.. EPSS estimates a 3.05% chance of exploitation in the next 30 days.

Description

vBulletin through 5.3.x on Windows allows remote PHP code execution because a require_once call is reachable with an unauthenticated request that can include directory traversal sequences to specify an arbitrary pathname, and because ../ traversal is blocked but ..\ traversal is not blocked. For example, an attacker can make an invalid HTTP request containing PHP code, and then make an index.php?routestring= request with enough instances of ".." to reach an Apache HTTP Server log file.

Metrics

CVSS 3.1

9.8/10

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

EPSS Probability

3.05%

85.9th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-22

Affected Software

Vendor	Product	Versions	Update
Vbulletin	Vbulletin	>= 5.0.1, <= 5.3.3	—
Vbulletin	Vbulletin	5.0.0	Beta 11

References

https://blogs.securiteam.com/index.php/archives/3569Exploit, Third Party Advisory
https://blogs.securiteam.com/index.php/archives/3569Exploit, Third Party Advisory

Timeline

Published: Dec 14, 2017
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2017-17671?

How severe is CVE-2017-17671?

CVE-2017-17671 has a CVSS score of 9.8/10 (CRITICAL severity). The EPSS model estimates a 3.05% probability of exploitation in the next 30 days.

How do I fix CVE-2017-17671?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2017-17671?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST