CVE-2023-42801
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedMoonlight-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.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysisA fixed-size buffer is filled without checking the length of the incoming data, so it overflows into neighbouring memory. This is the classic overflow attackers use to overwrite return addresses and hijack execution. The fix is strict length checks and safe, bounded string and memory functions.
General guidance for the classic buffer overflow class — the official description and references above are authoritative for this specific CVE. Want a bespoke review and a reviewed fix? Ask our team →
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data>= 2016-10-05, < 2023-10-06< 9.0.0< 12.0< 0.10.23< 2.6.1<= 1.14.5< 1.6.0< 0.13.4all versions<= 5.0.0CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- Required
- Scope
- Unchanged
- Confidentiality
- Low
- Integrity
- Low
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:H
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
dbcve · scoped0.10.230.13.41.6.0
moonlight-common-c version/commit b2497a3918a6d79808d9fd0c04734786e70d5954 or later; respective client versions as listed above
- 1. Identify which Moonlight client implementation you are using (Qt/pc, Android, iOS/tvOS, Embedded, Xbox, Tv, Switch, or Vita)
- 2. For the identified client, upgrade to a version released after October 6, 2023 that includes the patched moonlight-common-c library
- 3. Verify the upgrade by checking the client version matches or exceeds: Moonlight Qt/pc > 5.0.0, Moonlight (general) >= 12.0 or >= 10.23 depending on platform, Moonlight Embedded >= 2.6.1, Moonlight Xbox >= 1.14.6, Moonlight Tv >= 1.6.0, Moonlight Switch >= 0.13.4
- 4. For Moonlight Vita (all versions), there may be no patched version available; consider migrating to an alternative client
Generated from the published advisory — verify against the referenced sources before acting.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2023-42801 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2023-42801 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
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