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Fencer Vulns
critical 9.9

CVE-2020-27483 json

Garmin Forerunner 235 before 8.20 is affected by: Array index error.

published 2020-11-16 5 y ago modified 2026-06-17 4 mo ago also EUVD-2020-19993

cvss
9.9
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
2.1%
EPSS 2.1% chance of exploitation in 30 days, percentile 82%
public exploits
0
none known

Summary

Garmin Forerunner 235 before 8.20 is affected by: Array index error. 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 offset provided for the stack value duplication instruction, DUP. The offset is unchecked and memory prior to the start of the execution stack can be read and treated as a TVM object. A successful exploit could use the vulnerability to leak runtime information such as the heap handle or pointer for a number of TVM context variables. Some reachable values may be controlled enough to forge a TVM object on the stack, leading to possible remote code execution.

Patch / fix

  • garmin forerunner_235_firmware 8.20

Exploit prediction

2.15% chance of exploitation in the next 30 days, higher than 82% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/atredispartners/advisories/blob/master/ATREDIS-2020-0007.md referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 9.9 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
NVD 2.0 6.5 AV:N/AC:L/Au:S/C:P/I:P/A:P

Classification

Weakness
  • CWE-129 Improper Validation of Array Index

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.