How severe is CVE-2023-42801?

CVE-2023-42801 has a CVSS 3.x base score of 7.6, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity low, and availability high.

Is CVE-2023-42801 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (52nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2023-42801?

CVE-2023-42801 primarily affects Moonlight-stream Moonlight-common-c. In total, 11 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2023-42801?

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

When was CVE-2023-42801 published?

CVE-2023-42801 was published on 2023-12-14 and last updated on 2026-06-17.

CVE-2023-42801

CVE-2023-42801 is a high-severity vulnerability in Moonlight-stream Moonlight-common-c with a CVSS 3.x base score of 7.6. 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: High (CVSS 3.x base score 7.6)
EPSS exploit prediction: 1% (52nd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-120
Affected product: Moonlight-stream Moonlight-common-c
Published: 2023-12-14
Last modified: 2026-06-17

Description

Moonlight-common-c contains the core GameStream client code shared between Moonlight clients. Moonlight-common-c is vulnerable to buffer overflow starting in commit f57bd745b4cbed577ea654fad4701bea4d38b44c. A malicious game streaming server could exploit a buffer overflow vulnerability to crash a moonlight client. Achieving RCE is possible but unlikely, due to stack canaries in use by modern compiler toolchains. The published binaries for official clients Qt, Android, iOS/tvOS, and Embedded are built with stack canaries, but some unofficial clients may not use stack canaries. This vulnerability takes place after the pairing process, so it requires the client to be tricked into pairing to a malicious host. It is not possible to perform using a man-in-the-middle due to public key pinning that takes place during the pairing process. The bug was addressed in commit b2497a3918a6d79808d9fd0c04734786e70d5954.

Frequently asked questions

What is CVE-2023-42801?: Moonlight-common-c contains the core GameStream client code shared between Moonlight clients. Moonlight-common-c is vulnerable to buffer overflow starting in commit f57bd745b4cbed577ea654fad4701bea4d38b44c. A malicious game streaming server could exploit a buffer overflow vulnerability to crash a moonlight client. Achieving RCE is possible but unlikely, due to stack canaries in use by modern compiler toolchains. The published binaries for official clients Qt, Android, iOS/tvOS, and Embedded are built with stack canaries, but some unofficial clients may not use stack canaries. This vulnerability takes place after the pairing process, so it requires the client to be tricked into pairing to a malicious host. It is not possible to perform using a man-in-the-middle due to public key pinning that takes place during the pairing process. The bug was addressed in commit b2497a3918a6d79808d9fd0c04734786e70d5954.
How severe is CVE-2023-42801?: CVE-2023-42801 has a CVSS 3.x base score of 7.6, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity low, and availability high.
Is CVE-2023-42801 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (52nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2023-42801?: CVE-2023-42801 primarily affects Moonlight-stream Moonlight-common-c. In total, 11 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2023-42801?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2023-42801 published?: CVE-2023-42801 was published on 2023-12-14 and last updated on 2026-06-17.

References

Affected products (11)

cpe:2.3:a:moonlight-stream:moonlight-common-c:*:*:*:*:*:*:*:*
cpe:2.3:a:moonlight-stream:moonlight:*:*:*:*:*:iphone_os:*:*
cpe:2.3:a:moonlight-stream:moonlight:*:*:*:*:*:tvos:*:*
cpe:2.3:a:moonlight-stream:moonlight:*:*:*:*:*:android:*:*
cpe:2.3:a:moonlight-stream:moonlight:*:*:*:*:*:chrome:*:*
cpe:2.3:a:moonlight-stream:moonlight_embedded:*:*:*:*:*:*:*:*
cpe:2.3:a:moonlight-stream:moonlight_xbox:*:*:*:*:*:*:*:*
cpe:2.3:a:moonlight-stream:moonlight_tv:*:*:*:*:*:*:*:*
cpe:2.3:a:moonlight-stream:moonlight_switch:*:*:*:*:*:*:*:*
cpe:2.3:a:moonlight-stream:moonlight_vita:*:*:*:*:*:*:*:*
cpe:2.3:a:moonlight-stream:moonlight_qt\/pc:*:*:*:*:*:*:*:*

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