CVE Explorer
CVE-2026-48109
MessagePack for C# is a MessagePack serializer for C#. Prior to 2.5.301 and 3.1.7, A vulnerability exists in the optional LZ4 decompression path used by MessagePack compression modes Lz4Block and Lz4BlockArray. The decoder implementation is based on a deprecated fast-decompression algorithm that does not take a source-length bound. A remote attacker can send a crafted MessagePack payload with manipulated LZ4 token/length fields to force out-of-bounds reads from the compressed input buffer. In af
Known exploited
Not asserted
Disputed
No
Stale source
No
Conflicts
0
Affected products and versions
1 source assertion{"product":"MessagePack-CSharp","vendor":"MessagePack-CSharp","versions":[{"status":"affected","version":">= 3.1.7, < 3.1.7"},{"status":"affected","version":"< 2.5.301"}]}
- cve_program_cvelist_v5affectedurn:baitaphish:normalized-source-record:v2:acc3e45a62bf1c9057a4ae47b74ffee38531ae4f9eb2ad2867df433b3962e8e0 · sha256:d9d0b1c4669a3559… · /containers/cna/affected/0
Provider-owned CVSS observations
1 source assertion{"metric":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"HIGH","baseScore":8.2,"baseSeverity":"HIGH","confidentialityImpact":"LOW","integrityImpact":"NONE","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H","version":"3.1"},"metric_type":"cvssV3_1"}
- cve_program_cvelist_v5cvssurn:baitaphish:normalized-source-record:v2:acc3e45a62bf1c9057a4ae47b74ffee38531ae4f9eb2ad2867df433b3962e8e0 · sha256:d9d0b1c4669a3559… · /containers/cna/metrics/0/cvssV3_1
CWE assertions
1 source assertion{"cweId":"CWE-20","description":"CWE-20: Improper Input Validation","lang":"en","type":"CWE"}
- cve_program_cvelist_v5cweurn:baitaphish:normalized-source-record:v2:acc3e45a62bf1c9057a4ae47b74ffee38531ae4f9eb2ad2867df433b3962e8e0 · sha256:d9d0b1c4669a3559… · /containers/cna/problemTypes/0/descriptions/0
Source references
1 source assertion{"name":"https://github.com/MessagePack-CSharp/MessagePack-CSharp/security/advisories/GHSA-hv8m-jj95-wg3x","tags":["x_refsource_CONFIRM"],"url":"https://github.com/MessagePack-CSharp/MessagePack-CSharp/security/advisories/GHSA-hv8m-jj95-wg3x"}
- cve_program_cvelist_v5referenceurn:baitaphish:normalized-source-record:v2:acc3e45a62bf1c9057a4ae47b74ffee38531ae4f9eb2ad2867df433b3962e8e0 · sha256:d9d0b1c4669a3559… · /containers/cna/references/0
Attribution and limitations
- CVE Program CVEList V5: Reproduce the MITRE copyright designation and CVE license in copies. Source →
Provider severity values are preserved separately. Baitaphish does not convert them into a risk rating, infer affected products, or treat EPSS as observed exploitation.