How severe is CVE-2020-27486?

CVE-2020-27486 has a CVSS 3.x base score of 9.9, rated critical severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2020-27486 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (77th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-27486?

CVE-2020-27486 affects Garmin Forerunner 235 Firmware. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2020-27486?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2020-27486 published?

CVE-2020-27486 was published on 2020-11-16 and last updated on 2026-06-17.

CVE-2020-27486

CVE-2020-27486 is a critical-severity vulnerability in Garmin Forerunner 235 Firmware with a CVSS 3.x base score of 9.9. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-120.

Key facts

Severity: Critical (CVSS 3.x base score 9.9)
CVSS v2: 6.5
EPSS exploit prediction: 2% (77th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-120
Affected product: Garmin Forerunner 235 Firmware
Published: 2020-11-16
Last modified: 2026-06-17

Description

Garmin Forerunner 235 before 8.20 is affected by: Buffer Overflow. The component is: ConnectIQ TVM. The attack vector is: To exploit the vulnerability, the attacker must upload a malicious ConnectIQ application to the ConnectIQ store. The ConnectIQ program interpreter trusts the string length provided in the data section of the PRG file. It allocates memory for the string immediately, and then copies the string into the TVM object by using a function similar to strcpy. This copy can exceed the length of the allocated string data and overwrite heap data. A successful exploit would allow a ConnectIQ app store application to escape and perform activities outside the restricted application execution environment.

Frequently asked questions

What is CVE-2020-27486?: Garmin Forerunner 235 before 8.20 is affected by: Buffer Overflow. The component is: ConnectIQ TVM. The attack vector is: To exploit the vulnerability, the attacker must upload a malicious ConnectIQ application to the ConnectIQ store. The ConnectIQ program interpreter trusts the string length provided in the data section of the PRG file. It allocates memory for the string immediately, and then copies the string into the TVM object by using a function similar to strcpy. This copy can exceed the length of the allocated string data and overwrite heap data. A successful exploit would allow a ConnectIQ app store application to escape and perform activities outside the restricted application execution environment.
How severe is CVE-2020-27486?: CVE-2020-27486 has a CVSS 3.x base score of 9.9, rated critical severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2020-27486 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (77th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-27486?: CVE-2020-27486 affects Garmin Forerunner 235 Firmware. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2020-27486?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2020-27486 published?: CVE-2020-27486 was published on 2020-11-16 and last updated on 2026-06-17.

References

https://github.com/atredispartners/advisories/blob/master/ATREDIS-2020-0006.md

Affected products (1)

cpe:2.3:o:garmin:forerunner_235_firmware:*:*:*:*:*:*:*:*

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