CVE-2020-4060

CVE-2020-4060 is a medium-severity vulnerability in Semtech Lora Basics Station with a CVSS 3.x base score of 4.1. 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-416.

Key facts

Description

In LoRa Basics Station before 2.0.4, there is a Use After Free vulnerability that leads to memory corruption. This bug is triggered on 32-bit machines when the CUPS server responds with a message (https://doc.sm.tc/station/cupsproto.html#http-post-response) where the signature length is larger than 2 GByte (never happens in practice), or the response is crafted specifically to trigger this issue (i.e. the length signature field indicates a value larger than (2**31)-1 although the signature actually does not contain that much data). In such a scenario, on 32 bit machines, Basic Station would execute a code path, where a piece of memory is accessed after it has been freed, causing the process to crash and restarted again. The CUPS transaction is typically mutually authenticated over TLS. Therefore, in order to trigger this vulnerability, the attacker would have to gain access to the CUPS server first. If the user chose to operate without authentication over TLS but yet is concerned about this vulnerability, one possible workaround is to enable TLS authentication. This has been fixed in 2.0.4.

Frequently asked questions

What is CVE-2020-4060?
In LoRa Basics Station before 2.0.4, there is a Use After Free vulnerability that leads to memory corruption. This bug is triggered on 32-bit machines when the CUPS server responds with a message (https://doc.sm.tc/station/cupsproto.html#http-post-response) where the signature length is larger than 2 GByte (never happens in practice), or the response is crafted specifically to trigger this issue (i.e. the length signature field indicates a value larger than (2**31)-1 although the signature actually does not contain that much data). In such a scenario, on 32 bit machines, Basic Station would execute a code path, where a piece of memory is accessed after it has been freed, causing the process to crash and restarted again. The CUPS transaction is typically mutually authenticated over TLS. Therefore, in order to trigger this vulnerability, the attacker would have to gain access to the CUPS server first. If the user chose to operate without authentication over TLS but yet is concerned about this vulnerability, one possible workaround is to enable TLS authentication. This has been fixed in 2.0.4.
How severe is CVE-2020-4060?
CVE-2020-4060 has a CVSS 3.x base score of 4.1, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and user interaction. Impact on confidentiality is none, integrity none, and availability low.
Is CVE-2020-4060 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (57th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-4060?
CVE-2020-4060 affects Semtech Lora Basics Station. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2020-4060?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2020-4060 published?
CVE-2020-4060 was published on 2020-06-22 and last updated on 2026-06-17.

References

Affected products (1)

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