CVE-2026-48510

Home/CVE/MessagePack for C# is a MessagePack serializer for C#. Prior to 2.5.301 and 3.1.7, when MessagePack-CSharp decompresses

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MessagePack for C# is a MessagePack serializer for C#. Prior to 2.5.301 and 3.1.7, when MessagePack-CSharp decompresses

MessagePack for C# is a MessagePack serializer for C#. Prior to 2.5.301 and 3.1.7, when MessagePack-CSharp decompresses Lz4Block or Lz4BlockArray payloads, it reads declared uncompressed lengths from the wire and allocates output buffers based on those lengths before validating that the compressed data is valid or that the declared expansion is reasonable. A small payload can claim a very large uncompressed length and force a large allocation before LZ4 decoding begins.

This vulnerability is fixed in 2.5.301 and 3.1.7.

Monitor

⚠ NVD has not scored this CVE yet - manual triage required (common for recent CVEs)

No Sigma yet — build one → YARA rules0

Look this up elsewhere - one-click external pivots

NVD CVE.org CISA Exploit-DB GitHub PoC VulnCheck KEV GreyNoise

▸ How to read a CVE - triage first, then detect and patch

This page is every public fact about CVE-2026-48510, cross-linked. Its job is to answer one question fast - does this need my attention now? - and then hand you the two things you do about it. Here is how an analyst reads it.

Triage: should I act now? Four signals, and they are not interchangeable:

CVSSseverity - how bad it is IF exploited, 0-10. A high CVSS alone is not urgency; a flaw can be a perfect 10 and never actually be attacked. EPSSprobability - a model’s estimate of the chance it is exploited in the next 30 days, 0-1. This is the “will it actually happen” signal. CISA KEVconfirmed - it is being exploited in the wild right now. The strongest signal on the page; KEV beats any score. Weaponisedavailability - public exploits / PoCs, and especially Metasploit modules rated Excellent / Great. Reliable, packaged exploit code means low-skill attackers can use it today.

How they combine: KEV, or a dependable Metasploit module, means patch now regardless of CVSS. High CVSS + low EPSS + no exploit is real but not an emergency - schedule it. Low CVSS but KEV-listed still gets patched now. The verdict above already weighed these for you; this is how it got there.

Then what - two workflows:

Detectwhen you cannot patch today, follow this CVE to the ATT&CK techniques it enables, then Build a SIEM detection (the green button) - author a rule, test it in Atomic, deploy it. That buys visibility while the patch waits. PatchAffected products / packages tell you if you are exposed; Fixed versions by distribution and Vendor advisories give the exact version that closes it.

Reading order for the panels below: verdict + badges, then Public exploits / Metasploit (is it weaponised), then ATT&CK techniques + Sigma / IDS rules (can I detect it), then Affected products / packages + Fixed versions (am I exposed, what patches it), then Threat actors / IOCs (who uses it), then Scoring & timeline / references (the evidence).

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ATT&CK techniques

Techniques this CVE enables. Pills with a solid outline are high confidence - named directly in ATT&CK or Nuclei, or human-curated by CTID; the rest are inferred from the weakness type using MITRE's CVE Mapping Methodology and the CWE → CAPEC chain. Broad, generic-weakness guesses are filtered out. A small N× marks a technique that N independent sources agree on.

T1498.001 · Direct Network Flood T1498.002 · Reflection Amplification T1499 · Endpoint Denial of Service T1499.001 · OS Exhaustion Flood T1499.002 · Service Exhaustion Flood T1499.003 · Application Exhaustion Flood

▤ Build a SIEM detection for these techniques

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CAPEC attack patterns

Attack patterns this CVE enables - the bridge from weakness to ATT&CK technique.

CAPEC-CAPEC-125 · Flooding CAPEC-CAPEC-130 · Excessive Allocation CAPEC-CAPEC-147 · XML Ping of the Death CAPEC-CAPEC-197 · Exponential Data Expansion CAPEC-CAPEC-229 · Serialized Data Parameter Blowup CAPEC-CAPEC-230 · Serialized Data with Nested Payloads CAPEC-CAPEC-231 · Oversized Serialized Data Payloads CAPEC-CAPEC-469 · HTTP DoS CAPEC-CAPEC-482 · TCP Flood CAPEC-CAPEC-486 · UDP Flood CAPEC-CAPEC-487 · ICMP Flood CAPEC-CAPEC-488 · HTTP Flood

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Weakness Classification

CWE-409Improper Handling of Highly Compressed Data (Data Amplification)

CWE-770Allocation of Resources Without Limits or Throttling

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Related CVEs

CVEs linked to this one by a shared weakness (CWE) or affected product - joins on data already in the engine, with the reason shown per row. Not a guess.

CVE-2017-16129 The HTTP client module superagent is vulnerable to ZIP bomb attacks. In a ZIP bo... same CWE-409 MEDIUM CVE-2022-29225 Envoy is a cloud-native high-performance proxy. In versions prior to 1.22.1 seco... same CWE-409 HIGH CVE-2022-37439 In Splunk Enterprise and Universal Forwarder versions in the following table, in... same CWE-409 MEDIUM CVE-2023-0475 HashiCorp go-getter up to 1.6.2 and 2.1.1 is vulnerable to decompression bombs. ... same CWE-409 MEDIUM CVE-2001-1388 iptables before 1.2.4 does not accurately convert rate limits that are specified... same CWE-770 CVE-2005-2970 Memory leak in the worker MPM (worker.c) for Apache 2, in certain circumstances,... same CWE-770 CVE-2005-4650 Joomla! 1.03 does not restrict the number of "Search" Mambots, which allows remo... same CWE-770 MEDIUM CVE-2008-1700 The Web TransferCtrl Class 8,2,1,4 (iManFile.cab), as used in WorkSite Web 8.2 b... same CWE-770

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References & Sources

Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.

https://github.com/MessagePack-CSharp/MessagePack-CSharp/security/advisories/GHSA-v72x-2h86-7f8m