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CVE-2017-17671· NVD / CVE Program· CNA mitre

vBulletin through 5.3.x on Windows allows remote PHP code execution because a require_once call is reachable with an unauthenticated request

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.

CriticalCVSS 9.8 · v3.1—No exploit No fix recorded
Published
Dec 13, 2017
Updated
Jun 16, 2026
EPSS
3.1% · 87th percentile
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Report tools

JSON

Action score

40

Plan

Add it to your regular patch cycle.

CVSS
39 / 40 · 9.8 / 10
CISA KEV
0 / 30 · Not listed
EPSS
1 / 30 · 3.1%

Affected systems

VendorProduct
vbulletinvbulletin
microsoftwindows

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • vbulletin vbulletin5.0.1 and later · up to 5.3.3 inclusive
  • vbulletin vbulletin5.0.0

Same product

vbulletin: all records

Other highest-scoring records for the same primary product.

  • CVE-2019-16759vBulletin 5.x through 5.5.4 allows remote command execution via the widgetConfig[code] parameter in an ajax/render/widget_php routestring reKEV
    99Now
  • CVE-2020-17496vBulletin 5.5.4 through 5.6.2 allows remote command execution via crafted subWidgets data in an ajax/render/widget_tabbedcontainer_tab_panelKEV
    95Now
  • CVE-2020-12720vBulletin before 5.5.6pl1, 5.6.0 before 5.6.0pl1, and 5.6.1 before 5.6.1pl1 has incorrect access control.
    66This week
  • CVE-2025-48827vBulletin 5.0.0 through 5.7.5 and 6.0.0 through 6.0.3 allows unauthenticated users to invoke protected API controllers' methods when running
    62This week
  • CVE-2016-6195SQL injection vulnerability in forumrunner/includes/moderation.php in vBulletin before 4.2.2 Patch Level 5 and 4.2.3 before Patch Level 1 al
    60This week
  • CVE-2015-7808The vB_Api_Hook::decodeArguments method in vBulletin 5 Connect 5.1.2 through 5.1.9 allows remote attackers to conduct PHP object injection a
    54Plan

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

No fix version is recorded for this entry. Check the references for vendor advisories.

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
high · data can be read
Integrity
high · data or configuration can be modified
Availability
high · the service can be disrupted
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

CWE-22 · Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

CVSS vector

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

nvd-primary

Root cause

A user-supplied file name is joined with the allowed directory, but the result is never checked to confirm it is still inside that directory.

The bug in code

The whole CWE-22 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

ts
const file = path.join(ROOT, req.query.name);res.sendFile(file);

Fixed

ts
const file = path.resolve(ROOT, req.query.name);if (!file.startsWith(ROOT + path.sep)) {  return res.sendStatus(400);}res.sendFile(file);

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

ATT&CK techniques

—

Noroxi analysis

No Noroxi analysis for this record yet

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Change log

No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.

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