PatchSiren

PatchSiren cyber security CVE debrief

CVE-2016-9417 Mybb CVE debrief

CVE-2016-9417 is a server-side request forgery (SSRF) issue in MyBB and MyBB Merge System versions before 1.8.8. The flaw is identified in the fetch_remote_file function and was assigned a HIGH severity score by NVD. The main security concern is that a remote attacker may be able to make the forum server initiate requests to attacker-influenced destinations, which can expose internal services or other network-reachable resources. Vendor release notes indicate the fix shipped in MyBB 1.8.8 / Merge System 1.8.8.

Vendor
Mybb
Product
Merge System
CVSS
HIGH 7.4
CISA KEV
Not listed in stored evidence
Original CVE published
2017-01-31
Original CVE updated
2026-05-13
Advisory published
2017-01-31
Advisory updated
2026-05-13

Who should care

Administrators and security teams running MyBB or MyBB Merge System 1.8.7 or earlier should treat this as relevant. It is especially important for internet-facing deployments, forums with user-supplied URLs or remote content features, and environments where the application server can reach internal network services.

Technical summary

NVD maps this issue to CWE-918 (SSRF) and lists affected CPE ranges ending at version 1.8.7 for both MyBB and MyBB Merge System. The CVSS 3.0 vector is AV:N/AC:L/PR:N/UI:R/S:C/C:N/I:H/A:N, indicating a network-reachable issue with no privileges required but with user interaction needed and a high integrity impact in the scope of the affected system. The public description names fetch_remote_file as the vulnerable function, but the available corpus does not specify the exact input path or triggering workflow, so defensive guidance should focus on restricting outbound server requests and upgrading to the fixed release.

Defensive priority

High. This is a network-facing SSRF flaw with a vendor fix available and a CVSS base score of 7.4. Even without proof of active exploitation in the supplied corpus, SSRF can enable internal network probing or unintended server-side access, so patching should be prioritized.

Recommended defensive actions

  • Upgrade MyBB and MyBB Merge System to 1.8.8 or later.
  • Review any features that fetch remote URLs or external content and restrict them to trusted sources.
  • Limit the application server's outbound network access with firewall or egress controls where feasible.
  • Monitor logs for unusual outbound requests originating from the forum server.
  • If immediate patching is not possible, disable or constrain any functionality that invokes remote fetching until the upgrade is complete.

Evidence notes

The description identifies fetch_remote_file as the affected function and states the flaw is present before 1.8.8 in both MyBB and MyBB Merge System. NVD classifies the weakness as CWE-918 and provides the CVSS 3.0 vector AV:N/AC:L/PR:N/UI:R/S:C/C:N/I:H/A:N. The NVD CPE criteria mark versions through 1.8.7 as vulnerable. Vendor release notes for 1.8.8 are included in the source corpus, along with related oss-security mailing list references and a SecurityFocus entry, supporting the fix timeline and impact context.

Sources and references

Verified primary and authoritative sources

  • CVE-2016-9417 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2016-9417

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2016-9417 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2016-9417

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.