CVE-2017-17671

critical

Published 2017-12-14 · Modified 2026-05-13

CVSS v3

9.8

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

CVSS v2

7.5

VIR risk

9.8

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.

Predictions

Exploit likelihood

97%

Patch ETA

—

Heuristic predictions, AS-IS, for prioritization only.

Mitigations

No vendor mitigations ingested yet for this CVE. The mitigation-content worker queues fetches as references arrive — check back in a few minutes, or see the references list below.

Application impact

Vendor	Product	Versions	Fixed
vbulletin	vbulletin	`{"startIncluding":"5.0.1","endIncluding":"5.3.3"}`
vbulletin	vbulletin	`5.0.0`

References

CWEs

CWE-22

Verify integrity in audit chain (admin only). AS-IS.