Endpoint AntivirusApplication · Eset

CVE-2020-26941

MEDIUM · 5.5 CVSS v3.1 Published 2021-01-26
Fix available
A fix is available. Upgrade to after 13.2 or later.
See remediation →
57/100
Remediation priority · Elevated
Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
A local (authenticated) low-privileged user can exploit a behavior in an ESET installer to achieve arbitrary file overwrite (deletion) of any file via a symlink, due to insecure permissions. The possibility of exploiting this vulnerability is limited and can only take place during the installation phase of ESET products. Furthermore, exploitation can only succeed when Self-Defense is disabled. Affected products are: ESET NOD32 Antivirus, ESET Internet Security, ESET Smart Security, ESET Smart Security Premium versions 13.2 and lower; ESET Endpoint Antivirus, ESET Endpoint Security, ESET NOD32 Antivirus Business Edition, ESET Smart Security Business Edition versions 7.3 and lower; ESET File Security for Microsoft Windows Server, ESET Mail Security for Microsoft Exchange Server, ESET Mail Security for IBM Domino, ESET Security for Kerio, ESET Security for Microsoft SharePoint Server versions 7.2 and lower.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

A local authenticated low-privileged user can exploit insecure file permissions in the ESET installer to achieve arbitrary file overwrite or deletion via symbolic link attacks. The vulnerability only manifests during the installation phase and requires Self-Defense to be disabled, allowing symlink-based file manipulation.

MitigationEnsure Self-Defense is enabled during installation; upgrade to patched versions of ESET products (13.2+ for consumer, 7.4+ for endpoint, 7.3+ for server products) which address the insecure permission handling in the installer.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Endpoint AntivirusApplication
Affected:<= 7.3
Endpoint SecurityApplication
Affected:<= 7.3
File SecurityApplication
Affected:<= 7.2
Internet SecurityApplication
Affected:<= 13.2= 1294
Mail SecurityApplication
Affected:<= 7.2
Nod32 AntivirusApplication
Affected:<= 7.3<= 13.2
SecurityApplication
Affected:<= 7.2
Smart SecurityApplication
Affected:<= 7.3<= 13.2

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
High
Availability
None

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify installed ESET product and version
    Open Windows Control Panel > Programs and Features, or run: wmic product get name,version | findstr -i eset
    Affected if Version falls within affected ranges: Endpoint Antivirus/Security <=7.3, File Security <=7.2, Internet Security <=13.2 or =1294, Mail Security <=7.2, Nod32 Antivirus <=7.3 or <=13.2, Security <=7.2, Smart Security <=7.3 or <=13.2
  2. Verify Self-Defense status
    Open ESET main window > Setup > Computer Protection or Setup > Network Protection > Self-Defense. Check if Self-Defense is currently disabled.
    Affected if Self-Defense is disabled (the vulnerability manifests when Self-Defense is disabled during installation, allowing symlink-based file manipulation)
  3. Check for recent installer activity
    Review Windows Event Viewer > Application logs for ESET installer events, or check temp folders for ESET installer remnants within the last several weeks.
    Affected if ESET installer was run recently on the system (the vulnerability only manifests during the installation phase)

A user is affected if they have an ESET product version within the affected ranges AND the product was installed with Self-Defense disabled (the installer creates vulnerable symlink-handling permissions during that installation event).

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Upgrade available Upgrade to a release after 13.2
Interim mitigation

Ensure Self-Defense is enabled during installation; upgrade to patched versions of ESET products (13.2+ for consumer, 7.4+ for endpoint, 7.3+ for server products) which address the insecure permission handling in the installer.

Fix this in Endpoint Antivirus Scoped from the published advisory
  • Consultation3.0 h
  • Implementation6.0 h
  • Testing4.0 h
  • Review / QA2.0 h
15.0 hours of engineering $2,640
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Scan for this in your stack

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dbcve dependency scanner

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2020-26941 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data