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Patch first › TeamViewer

Exploited CVE from 2019, added in 2021

CVE-2019-18988

TeamViewer Desktop · Remote monitoring and management (RMM)

TeamViewer Desktop Bypass Remote Login Vulnerability

At a glance

Exploited. Added to CISA’s catalog of exploited vulnerabilities on November 3, 2021.

Affected product: TeamViewer Desktop (category Remote monitoring and management (RMM), indicative classification). Name in CISA’s catalog: TeamViewer Desktop.

What should I do?

Apply the security update from TeamViewer.

Deadline set by CISA for US federal agencies: 181 days (due May 3, 2022). It only binds those agencies, but it is a useful measure of urgency.

Original text of the required action (CISA)

Apply updates per vendor instructions.

Timeline

  1. Vulnerability published Publication date (NVD)
  2. Exploitation confirmed Added to CISA’s KEV catalog
  3. CISA deadline Remediation deadline set for US federal agencies

The facts, with their sources

Exploitation confirmed
Yes, on November 3, 2021 Date added to the catalog of exploited vulnerabilities. Exploitation itself may have started earlier. Source: KEV catalog, collected September 29, 2026 at 14:57 UTC
Ransomware
No known use to date That does not guarantee it is not being used: the information is not public. Source: KEV catalog, collected September 29, 2026 at 14:57 UTC
Hunt for compromise
Not requested by CISA Source: KEV catalog, collected September 29, 2026 at 14:57 UTC
CISA required action
Apply the security update from TeamViewer. Rewritten by this site from CISA’s original text. Source: KEV catalog, collected September 29, 2026 at 14:57 UTC
CISA deadline
May 3, 2022, 181 days Set for US federal agencies: a measure of urgency, not an obligation elsewhere. Source: KEV catalog, collected September 29, 2026 at 14:57 UTC
Vulnerability published
February 7, 2020 Source: National Vulnerability Database (NVD), collected September 29, 2026 at 15:00 UTC
Product according to CISA
TeamViewer Desktop Filed by this site under “Remote monitoring and management (RMM)” (indicative classification). Source: KEV catalog, collected September 29, 2026 at 14:57 UTC
CVSS vector
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H Technical detail of the score: attack vector, complexity, impact. Source: National Vulnerability Database (NVD), collected September 29, 2026 at 15:00 UTC

Severity and activity

7.0 / 10 CVSS severity: high

Score from the NVD. Collected Sep 29, 2026.

— Probability of exploitation in the next 30 days (EPSS)

FIRST’s EPSS model. Since exploitation is already confirmed, this figure is mostly useful to compare activity. Collected Sep 29, 2026.

Description

TeamViewer Desktop through 14.7.1965 allows a bypass of remote-login access control because the same key is used for different customers' installations. It used a shared AES key for all installations since at least as far back as v7.0.43148, and used it for at least OptionsPasswordAES in the current version of the product. If an attacker were to know this key, they could decrypt protect information stored in the registry or configuration files of TeamViewer. With versions before v9.x , this allowed for attackers to decrypt the Unattended Access password to the system (which allows for remote login to the system as well as headless file browsing). The latest version still uses the same key for OptionPasswordAES but appears to have changed how the Unattended Access password is stored. While in most cases an attacker requires an existing session on a system, if the registry/configuration keys were stored off of the machine (such as in a file share or online), an attacker could then decrypt the required password to login to the system.

Official description from the NVD, collected Sep 29, 2026. CVE® description © The MITRE Corporation.

TeamViewer Desktop allows for bypass of remote-login access control because the same AES key is used for different customers' installations. If an attacker were to know this key, they could decrypt protected information stored in registry or configuration files or decryption of the Unattended Access password to the system (which allows for remote login to the system).

Summary from CISA (KEV catalog).

CERT-FR advisories

No advisory among the latest CERT-FR publications this site follows. That does not mean there are none.

Information reused under the Open Licence 2.0 (Etalab); the date of last update is shown for each advisory. This site is neither affiliated with nor endorsed by ANSSI.

Sources for this page

  • CISA KEV catalog: exploitation, date added, required action, deadline, ransomware.
  • NVD (NIST): CVSS severity, publication date, description, vendor references.
  • EPSS (FIRST): probability of exploitation.
  • CERT-FR: advisories and alerts (in French).
  • Brand and category: indicative classification by this site (method).