How severe is CVE-2020-5234?

CVE-2020-5234 has a CVSS 3.x base score of 4.8, rated medium severity. It is exploitable over network with high attack complexity, requires low privileges and user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2020-5234 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (73rd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-5234?

CVE-2020-5234 primarily affects Messagepack. In total, 8 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2020-5234?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2020-5234 published?

CVE-2020-5234 was published on 2020-01-31 and last updated on 2026-06-17.

CVE-2020-5234

CVE-2020-5234 is a medium-severity vulnerability in Messagepack with a CVSS 3.x base score of 4.8. 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-787.

Key facts

Severity: Medium (CVSS 3.x base score 4.8)
CVSS v2: 6.8
EPSS exploit prediction: 2% (73rd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-787
Affected product: Messagepack
Published: 2020-01-31
Last modified: 2026-06-17

Description

MessagePack for C# and Unity before version 1.9.11 and 2.1.90 has a vulnerability where untrusted data can lead to DoS attack due to hash collisions and stack overflow. Review the linked GitHub Security Advisory for more information and remediation steps.

Frequently asked questions

What is CVE-2020-5234?: MessagePack for C# and Unity before version 1.9.11 and 2.1.90 has a vulnerability where untrusted data can lead to DoS attack due to hash collisions and stack overflow. Review the linked GitHub Security Advisory for more information and remediation steps.
How severe is CVE-2020-5234?: CVE-2020-5234 has a CVSS 3.x base score of 4.8, rated medium severity. It is exploitable over network with high attack complexity, requires low privileges and user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2020-5234 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (73rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-5234?: CVE-2020-5234 primarily affects Messagepack. In total, 8 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2020-5234?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2020-5234 published?: CVE-2020-5234 was published on 2020-01-31 and last updated on 2026-06-17.

References

Affected products (8)

cpe:2.3:a:messagepack:messagepack:*:*:*:*:*:c\#:*:*
cpe:2.3:a:messagepack:messagepack:2.0.94:alpha:*:*:*:c\#:*:*
cpe:2.3:a:messagepack:messagepack:2.0.110:alpha:*:*:*:c\#:*:*
cpe:2.3:a:messagepack:messagepack:2.0.119:beta:*:*:*:c\#:*:*
cpe:2.3:a:messagepack:messagepack:2.0.123:beta:*:*:*:c\#:*:*
cpe:2.3:a:messagepack:messagepack:2.0.204:beta:*:*:*:c\#:*:*
cpe:2.3:a:messagepack:messagepack:2.0.270:rc:*:*:*:c\#:*:*
cpe:2.3:a:messagepack:messagepack:2.0.299:rc:*:*:*:c\#:*:*

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