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Actively exploited

CVE-2017-17562 Embedthis GoAhead Remote Code Execution Vulnerability

Embedthis GoAhead before 3.6.5 allows remote code execution if CGI is enabled and a CGI program is dynamically linked.

From the CISA KEV catalogue version 2026.11.06, with Cybergen analysis. Updated 6 Nov 2026.

Our Assessment

Should You Worry?

Patch urgentlyCybergen assessment
  • CISA confirmed exploitation in the wild and added it to the Known Exploited Vulnerabilities catalogue on 10 Dec 2021.
  • Rated High severity (CVSS 8.1, scored by CISA).
  • It has been in the catalogue for 1,792 days. Systems still unpatched now have almost certainly been scanned for it.
The Vulnerability

What It Is

Embedthis GoAhead before 3.6.5 allows remote code execution if CGI is enabled and a CGI program is dynamically linked. This is a result of initializing the environment of forked CGI scripts using untrusted HTTP request parameters in the cgiHandler function in cgi.c. When combined with the glibc dynamic linker, this behaviour can be abused for remote code execution using special parameter names such as LD_PRELOAD. An attacker can POST their shared object payload in the body of the request, and reference it using /proc/self/fd/0.

From Watch to Action

What To Do Now

  1. 1

    Find it

    Search your asset inventory and external attack surface for Embedthis GoAhead. Include cloud images, appliances and anything a supplier runs for you.

    Attack Surface Management
  2. 2

    Fix it

    Apply updates per vendor instructions.

    Vulnerability Management
  3. 3

    Hunt for compromise

    If an affected system was reachable before you patched, assume it may have been hit. Check logs, new accounts, web shells and outbound connections from the date of exposure.

    Incident Response
  4. 4

    Prove it is fixed

    Rescan or test the system after patching. Upgrades that fail silently and forgotten secondary instances are common.

    Penetration Testing

Vendor Advisories

Regulation

The Compliance Clock

Cyber EssentialsRated high, so if it affects devices in your Cyber Essentials scope, the update must be installed within 14 days of the vendor releasing it.NIS2If exploitation causes a significant incident, essential and important entities owe their CSIRT an early warning within 24 hours and a notification within 72 hours.DORAFinancial entities must classify ICT incidents and send an initial notification for a major incident within strict deadlines, with exploited flaws a common cause.US federal (BOD 22-01)Federal civilian agencies had until 10 Jun 2022 to remediate. A sensible benchmark for everyone else.

General guidance, not legal advice. Your obligations depend on your sector, scope and jurisdiction.

Stay Ahead

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Evidence

Sources

  1. CISA Known Exploited Vulnerabilities catalogue
  2. NVD: CVE-2017-17562
  3. CVE record: CVE-2017-17562
  4. FIRST EPSS
  5. github.com/elttam/advisories/tree/master/CVE-2017-17562
  6. securitytracker.com/id/1040702
  7. elttam.com.au/blog/goahead/
  8. exploit-db.com/exploits/43360/
  9. oracle.com/technetwork/security-advisory/cpuapr2018-3678067.html
  10. github.com/embedthis/goahead/commit/6f786c123196eb622625a920d54048629a7caa74
  11. github.com/embedthis/goahead/issues/249
  12. exploit-db.com/exploits/43877/