Denial of service via unchecked array dimensions
Published Jun 22, 2026 · Updated Jun 22, 2026
Resource exhaustion in MessagePack for C# before 2.5.301 and 3.0 through 3.1.6 allows remote attackers to interrupt services. Two-, three-, and four-dimensional array formatters allocate target arrays from payload-declared dimensions before checking their product against the encoded element count. Applications are exposed only when they deserialize untrusted MessagePack data into models containing multidimensional arrays; oversized declarations can exhaust memory, terminate containers, or impose severe allocation CPU cost.
Summary
What happened
Resource exhaustion in MessagePack for C# before 2.5.301 and 3.0 through 3.1.6 allows remote attackers to interrupt services. Two-, three-, and four-dimensional array formatters allocate target arrays from payload-declared dimensions before checking their product against the encoded element count. Applications are exposed only when they deserialize untrusted MessagePack data into models containing multidimensional arrays; oversized declarations can exhaust memory, terminate containers, or impose severe allocation CPU cost.
The record
- CVE
- CVE-2026-48515
- Published
- Jun 22, 2026
- Updated
- Jun 22, 2026
- Vendor
- MessagePack-CSharp
- Product
- MessagePack for C#
- Classifications
- CWE-770, T1499.003
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jun 22, 2026CVE publishedPublication date reported by the CVE source.
- Jun 22, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=< 2.5.301
- Affected versionversion=>= 3.1.7, < 3.1.7
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
No public exploit references are available in this record.
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Technologies
Your stack
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Your stack
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