CVE-2023-42801· NVD / CVE Program· CNA GitHub_M

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

Noroxi assessment

Priority: Monitor (action score 30/100)

The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
Probability of exploitation in the next 30 days: 0.93% (FIRST EPSS); higher than 60.3% of all records.
Anyone who can reach it over the internet can trigger it. No account or password is required. A user must open a link or visit a page. No special conditions are required; it is repeatable.
No fixed version is recorded, but the references include a patch (commit or PR) link.

Low priority for now. See the fix and affected versions sections below.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

HighCVSS 7.6 · v3.1—No exploit No fix recorded

BDU:2024-00265

Published: Dec 14, 2023
Updated: Jun 17, 2026
EPSS: 0.9% · 60th percentile
CWE: CWE-120

Report tools

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Action score

Monitor

Low priority for now.

CVSS: 30 / 40 · 7.6 / 10
CISA KEV: 0 / 30 · Not listed
EPSS: 0 / 30 · 0.9%

CNA vs NVD score

NVD: 7.6
CNA · GitHub_M: 7.6; agree

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

Not in KEV: no record of exploitation in the wild
No public exploit code on record
No fixed version yet

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

Vendor	Product	CPE
moonlight-stream	moonlight-common-c	cpe:2.3:a:moonlight-stream:moonlight-common-c
moonlight-stream	moonlight	cpe:2.3:a:moonlight-stream:moonlight
moonlight-stream	moonlight embedded	cpe:2.3:a:moonlight-stream:moonlight_embedded
moonlight-stream	moonlight xbox	cpe:2.3:a:moonlight-stream:moonlight_xbox
moonlight-stream	moonlight tv	cpe:2.3:a:moonlight-stream:moonlight_tv
moonlight-stream	moonlight switch	cpe:2.3:a:moonlight-stream:moonlight_switch
moonlight-stream	moonlight vita	cpe:2.3:a:moonlight-stream:moonlight_vita
moonlight-stream	moonlight qt\/pc	cpe:2.3:a:moonlight-stream:moonlight_qt\/pc

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

moonlight-stream moonlightbefore 9.0.0
moonlight-stream moonlightbefore 12.0
moonlight-stream moonlightbefore 0.10.23
moonlight-stream moonlight embeddedbefore 2.6.1
moonlight-stream moonlight qt/pcup to 5.0.0 inclusive
moonlight-stream moonlight switchbefore 0.13.4
moonlight-stream moonlight tvbefore 1.6.0
moonlight-stream moonlight vitaall versions
moonlight-stream moonlight xboxup to 1.14.5 inclusive
moonlight-stream moonlight-common-c2016-10-05 and later · before 2023-10-06

Versions reported by the vendor

Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.

moonlight-stream moonlight-common-c
- >= f57bd745b4cbed577ea654fad4701bea4d38b44c, < b2497a3918a6d79808d9fd0c04734786e70d5954affected

Same product

moonlight-stream: all records

Other highest-scoring records for the same primary product.

CVE-2023-42800Buffer overflow due to use of `strcpy` in `performRtspHandshake`
36Monitor
CVE-2023-42799Buffer overflow due to use of `strcpy` in `parseUrlAddrFromRtspUrlString`
36Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

No fix version is recorded for this entry. Check the references for vendor advisories.

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

CVE-2023-427990 days apartBuffer overflow due to use of `strcpy` in `parseUrlAddrFromRtspUrlString`
36Monitor
CVE-2023-428000 days apartBuffer overflow due to use of `strcpy` in `performRtspHandshake`
36Monitor

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

Anyone who can reach it over the internet can trigger it.
No account or password is required.
A user must open a link or visit a page.
No special conditions are required; it is repeatable.

If successful

Confidentiality: low · data can be read
Integrity: low · data or configuration can be modified
Availability: high · the service can be disrupted

Attack vector: Network
Attack complexity: Low
Privileges required: None
User interaction: Required
Scope: Unchanged
Confidentiality impact: Low
Integrity impact: Low
Availability impact: High

Weakness class (CWE)

CWE-120 · Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:H

nvd-primary

Root cause

When data is copied, the source length is not compared with the size of the destination buffer. Excess data overwrites adjacent memory.

The bug in code

The whole CWE-120 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

1char buf[256];
2memcpy(buf, pkt->data, pkt->len);

Fixed

1char buf[256];
2if (pkt->len > sizeof(buf)) {
3  return -EINVAL;
4}
5memcpy(buf, pkt->data, pkt->len);

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

Attack patterns (CAPEC)

ATT&CK techniques

—

Change log

No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.

References

github.com/moonlight-stream/moonlight-common-c/commit/b2497a3918a6d79808d9fd0c04734786e70d5954

Show all references (1 more)

github.com/moonlight-stream/moonlight-common-c/commit/f57bd745b4cbed577ea654fad4701bea4d38b44c

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records