Read the docs
TI-2026-69613 Aliases CVE-2026-107296GHSA-qw35-55vc-rhgj

msgpack5 decoding modifies the input buffer for negative int64 values

Priority LOW 17CWE-471Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
High
Impact type
—
Confidentiality · integrity · availability
None · Low · None
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub.

Summary

msgpack5 versions before 6.1.0 are affected, the msgpack v5 implementation for Node.js and the browser. Decoding a negative signed 64-bit integer changes the matching bytes in the caller-provided input buffer, which is modification of assumed-immutable data (CWE-471). Applications that keep or reuse encoded input for integrity checks, logging or later processing can silently read corrupted data, while positive integers and other value types are unaffected.

Written with Claude Haiku 5.5 from the sources below · 2026-10-29

Description from the CNA

msgpack5 is a msgpack v5 implementation for node.js and the browser. Prior to 6.1.0, decoding a negative signed 64-bit integer modifies the corresponding bytes in the caller-provided input buffer while computing the value. Applications that retain or reuse encoded input for integrity checks, logging, or later processing can observe silently corrupted data, while positive integers and other MessagePack value types are unaffected. This issue is fixed in version 6.1.0.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00276 20th percentileScored 2026-11-07
Fix Fixed msgpack5 (mcollina): 6.1.0msgpack5 (npm): 6.1.0

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
mcollinamsgpack5before 6.1.06.1.0Patch availableCNA
—msgpack5 (npm)before 6.1.06.1.0Patch availableGHSA-qw35-55vc-rhgj
  • msgpack5 Vendormcollina Affected before 6.1.0 Fixed in 6.1.0 Patch available CNA
  • msgpack5 (npm) Vendor— Affected before 6.1.0 Fixed in 6.1.0 Patch available GHSA-qw35-55vc-rhgj

Remediation

Upgrade the npm package msgpack5 to version 6.1.0, which fixes the issue.

Written with Claude Haiku 5.5 from the sources below · 2026-10-29

  • Fix · CNA msgpack5 (mcollina) Fixed in 6.1.0
  • Fix · GHSA-qw35-55vc-rhgj msgpack5 (npm) Fixed in 6.1.0 Advisory →

Timeline

  1. 2026-10-08 Threatist record created from CVE-2026-107296
  2. 2026-10-08 Alias added: GHSA-qw35-55vc-rhgj
  3. 2026-10-14 CISA SSVC decision points changed

References

Other 4

  • TI-2026-76780 Command injection in mcollina mcp-ripgrep Advanced Search Tool CVSS 4.0MEDIUM 4.8
  • TI-2026-69605 Truncated map32 headers throw RangeError in msgpack5 decoder CVSS 3.1HIGH 7.5
  • TI-2026-69603 msgpack5 streaming decoder recursion can exhaust the call stack CVSS 3.1HIGH 7.5
  • TI-2026-69599 Deeply nested input exhausts the stack in msgpack5 decoder CVSS 3.1MEDIUM 5.3
  • TI-2026-69606 Prototype pollution in msgpack5 with partial options CVSS 3.1MEDIUM 6.5
  • TI-2026-69609 Quadratic parsing in msgpack5 streaming decoder blocks the event loop CVSS 3.1MEDIUM 5.9
See all 7 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences