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Fencer Vulns
critical 9.9

CVE-2020-27485 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-2020-19995

cvss
9.9
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.7%
EPSS 1.7% chance of exploitation in 30 days, percentile 77%
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 fails to check the index provided when accessing the local variable in the LGETV and LPUTV instructions. This provides the ability to both read and write memory outside the bounds of the TVM context allocation. It can be leveraged to construct a use-after-free scenario, leading to a constrained read/write primitive across the entire MAX32630 address space. A successful exploit would allow a ConnectIQ app store application to escape and perform activities outside the restricted application execution environment.

Patch / fix

  • garmin forerunner_235_firmware 8.20

Exploit prediction

1.70% chance of exploitation in the next 30 days, higher than 77% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/atredispartners/advisories/blob/master/ATREDIS-2020-0005.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.