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Fencer Vulns
high 7.6

CVE-2023-42801 json

Stack buffer overflow due to `strcpy` into fixed size buffer in `extractVersionQuadFromString`

published 2023-12-14 2 y ago modified 2026-06-17 4 mo ago also EUVD-2023-47228

cvss
7.6
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.9%
EPSS 0.9% chance of exploitation in 30 days, percentile 61%
public exploits
0
none known

Summary

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.

Patch / fix

  • moonlight-stream moonlight-common-c 2023-10-06
  • moonlight-stream moonlight 0.10.23, 9.0.0, 12.0
  • moonlight-stream moonlight_embedded 2.6.1
  • moonlight-stream moonlight_tv 1.6.0
  • moonlight-stream moonlight_switch 0.13.4

Exploit prediction

0.94% chance of exploitation in the next 30 days, higher than 61% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/moonlight-stream/moonlight-common-c/security/advisories/GHSA-f3h8-j898-5h5v referenced PoC, tagged "exploit" by a source, unverified
  • github.com https://github.com/moonlight-stream/moonlight-common-c/blob/c1744de06938b5a5c8897a705be1bc6508dc7580/src/Misc.c#L82-L88 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 7.6 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:H
NVD 3.1 7.6 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:H

Affected products

  • moonlight-stream moonlight-common-c

Classification

Weakness
  • CWE-120 Buffer Copy without Checking Size of Input

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.