How severe is CVE-2017-17671?

CVE-2017-17671 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2017-17671 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (86th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2017-17671?

CVE-2017-17671 primarily affects Vbulletin. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2017-17671?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2017-17671 published?

CVE-2017-17671 was published on 2017-12-14 and last updated on 2026-06-17.

CVE-2017-17671

CVE-2017-17671 is a critical-severity vulnerability in Vbulletin with a CVSS 3.x base score of 9.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-22.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 7.5
EPSS exploit prediction: 3% (86th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-22
Affected product: Vbulletin
Published: 2017-12-14
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2017-17671?: 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.
How severe is CVE-2017-17671?: CVE-2017-17671 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2017-17671 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (86th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2017-17671?: CVE-2017-17671 primarily affects Vbulletin. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2017-17671?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2017-17671 published?: CVE-2017-17671 was published on 2017-12-14 and last updated on 2026-06-17.

References

https://blogs.securiteam.com/index.php/archives/3569

Affected products (3)

cpe:2.3:a:vbulletin:vbulletin:*:*:*:*:*:*:*:*
cpe:2.3:a:vbulletin:vbulletin:5.0.0:beta_11:*:*:*:*:*:*
cpe:2.3:a:vbulletin:vbulletin:5.0.0:beta_28:*:*:*:*:*:*

More vulnerabilities in Vbulletin

CVE-2025-48827 — Critical (CVSS 10.0): vBulletin 5.0.0 through 5.7.5 and 6.0.0 through 6.0.3 allows unauthenticated users to invoke protected API controllers'…
CVE-2023-25135 — Critical (CVSS 9.8): vBulletin before 5.6.9 PL1 allows an unauthenticated remote attacker to execute arbitrary code via a crafted HTTP…
CVE-2020-7373 — Critical (CVSS 9.8): vBulletin 5.5.4 through 5.6.2 allows remote command execution via crafted subWidgets data in an…
CVE-2020-17496 — Critical (CVSS 9.8): vBulletin 5.5.4 through 5.6.2 allows remote command execution via crafted subWidgets data in an…
CVE-2020-12720 — Critical (CVSS 9.8): vBulletin before 5.5.6pl1, 5.6.0 before 5.6.0pl1, and 5.6.1 before 5.6.1pl1 has incorrect access control.
CVE-2019-17132 — Critical (CVSS 9.8): vBulletin through 5.5.4 mishandles custom avatars.

All CVEs affecting Vbulletin →

Other CWE-22 (Path Traversal) vulnerabilities

CVE-2026-48282 — Critical (CVSS 10.0): ColdFusion versions 2025.9, 2023.20 and earlier are affected by an Improper Limitation of a Pathname to a Restricted…
CVE-2026-54917 — Critical (CVSS 10.0): SeaweedFS is a distributed storage system for object storage (S3), file systems, and Iceberg tables. Prior to 4.30, the…
CVE-2026-11429 — Critical (CVSS 10.0): Two endpoints in the Vault Service ScriptsController, shared by Altium Enterprise Server and Altium 365, accept file…
CVE-2026-34909 — Critical (CVSS 10.0): A malicious actor with access to the network could exploit a Path Traversal vulnerability found in UniFi OS devices to…
CVE-2026-7411 — Critical (CVSS 10.0): In Eclipse BaSyx Java Server SDK versions prior to 2.0.0-milestone-10, inadequate path normalization in the Submodel…
CVE-2026-36767 — Critical (CVSS 10.0): A path traversal vulnerability in the /content/images/add endpoint of shopizer v3.2.5 allows attackers write arbitrary…

Browse all CWE-22 (Path Traversal) vulnerabilities →