Vulnerability library
Security checkOctober 08, 2026

msgpack5: Decoding negative int64 values mutates the input buffer

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Low severitynpmmsgpack5

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Description

Decoding a negative signed 64-bit integer modifies the corresponding bytes in the caller-provided input buffer. Applications that retain or reuse encoded input for integrity checks, logging, or subsequent processing may observe silently corrupted data.

Positive integers and other MessagePack value types are not affected.

Recommendation

Update the msgpack5 package to the latest compatible version. Followings are version details:

  • Affected version(s): < 6.1.0
  • Patched version(s): 6.1.0

References

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Related Issues

See something that needs correcting? Let us knowUpdated October 08, 2026