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PatchSiren cyber security CVE debrief

CVE-2017-6416 Flexense CVE debrief

CVE-2017-6416 is a critical buffer overflow in Flexense SysGauge 1.5.18's SMTP connection verification logic. NVD rates it 9.8 (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H), and the public record ties the issue to a crafted SMTP daemon response that sends an overlong 220 "Service ready" string, which can lead to arbitrary code execution.

Vendor
Flexense
Product
Sysgauge
CVSS
CRITICAL 9.8
CISA KEV
Not listed in stored evidence
Original CVE published
2017-03-06
Original CVE updated
2026-05-13
Advisory published
2017-03-06
Advisory updated
2026-05-13

Who should care

Administrators and security teams responsible for Flexense SysGauge 1.5.18, especially environments where the application verifies SMTP servers or connects to untrusted SMTP endpoints. Asset owners should treat this as a high-priority exposure because the vulnerability is network-reachable and does not require authentication or user interaction.

Technical summary

The NVD record identifies a CWE-119 buffer overflow in SysGauge 1.5.18. The vulnerable behavior occurs during SMTP connection verification when the software processes a long 220 ("Service ready") response from a crafted SMTP daemon. NVD's CVSS v3.0 vector is AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H, consistent with remote exploitation potential and full impact on confidentiality, integrity, and availability.

Defensive priority

Immediate

Recommended defensive actions

  • Inventory all instances of Flexense SysGauge and confirm whether version 1.5.18 is deployed.
  • Upgrade to a Flexense-fixed release if one is available; otherwise isolate or remove the affected version from networks that can reach untrusted SMTP services.
  • Restrict or validate outbound SMTP verification targets so the application does not interact with arbitrary or hostile SMTP daemons.
  • Monitor for crashes or anomalous behavior during SMTP verification, which may indicate attempted exploitation.
  • Review any exposed systems for signs of unauthorized code execution and follow incident response procedures if suspicious activity is found.

Evidence notes

Source evidence is consistent across the official CVE/NVD record: the vulnerable CPE is flexense:sysgauge:1.5.18, the weakness is listed as CWE-119, and the CVSS v3.0 vector is AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. Public references include SecurityFocus BID 96568 and Exploit-DB 41479, indicating the issue was publicly documented.

Sources and references

Verified primary and authoritative sources

  • CVE-2017-6416 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2017-6416

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

  • CVE-2017-6416 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2017-6416

    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.