What is CVE-2017-5566?

CVE-2017-5566 is a medium-severity vulnerability in Avg Anti-Virus, classified under Uncontrolled Search Path Element. CVSS score: 6.7/10. Published 2017-03-21.

How severe is CVE-2017-5566?

Medium severity. CVSS v3 base score is 6.7 out of 10.

Vulnerability in Avg Anti-Virus

CVE-2017-5566

Code injection vulnerability in AVG Ultimate 17.1 (and earlier), AVG Internet Security 17.1 (and earlier), and AVG AntiVirus FREE 17.1 (and earlier) allows a local attacker to bypass a self-protection mechanism, inject arbitrary code, and take full control of any AVG process via a "DoubleAgent" attack. One perspective on this issue is that (1) these products do not use the Protected Processes feature, and therefore an attacker can enter an arbitrary Application Verifier Provider DLL under Image File Execution Options in the registry; (2) the self-protection mechanism is intended to block all local processes (regardless of privileges) from modifying Image File Execution Options for these products; and (3) this mechanism can be bypassed by an attacker who temporarily renames Image File Execution Options during the attack.

Published 2017-03-21 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 6.7 (Medium). Vector: CVSS:3.0/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.006 (47.5th percentile), scored 2026-09-30.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 48th percentile — 47.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.006 · newest: 0.006 · change: 0.000

Affected products

Avg Anti-Virus — versions 17.1
Avg Internet Security — versions 17.1
Avg Ultimate — versions 17.1

Weakness classification (CWE)

CWE-427 — Uncontrolled Search Path Element

References

cybellum.com/doubleagent-taking-full-control-antivirus/ (Third Party Advisory)
www.securityfocus.com/bid/97022 (VDB Entry, Third Party Advisory, vdb-entry)
cybellum.com/doubleagentzero-day-code-injection-and-persistence-technique/ (Technical Description, Third Party Advisory)

Frequently asked questions

What is CVE-2017-5566?: CVE-2017-5566 is a medium-severity vulnerability in Avg Anti-Virus, classified under Uncontrolled Search Path Element. CVSS score: 6.7/10. Published 2017-03-21.
How severe is CVE-2017-5566?: Medium severity. CVSS v3 base score is 6.7 out of 10.