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TI-2026-69603 Aliases CVE-2026-107300GHSA-5x5g-h9x8-2fh9

msgpack5 streaming decoder recursion can exhaust the call stack

Priority LOW 39CWE-674Published · Updated

Key facts

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

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub. Impact type from CWE-674.

Summary

msgpack5 versions before 6.1.0 are affected. The streaming decoder calls itself recursively for each complete MessagePack value in a chunk, an uncontrolled recursion flaw (CWE-674). A remote peer that sends one chunk containing many small valid values can exhaust the JavaScript call stack, interrupting the process or stream.

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, the streaming decoder recursively invokes itself for each complete MessagePack value remaining in a chunk. A remote peer can send one chunk containing many small valid values, causing recursion proportional to the value count, exhausting the JavaScript call stack, and interrupting the process or stream. This issue is fixed in version 6.1.0.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00426 37th 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
Yes
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-5x5g-h9x8-2fh9
  • 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-5x5g-h9x8-2fh9

Remediation

Upgrade the npm package msgpack5 to version 6.1.0, which fixes this 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-5x5g-h9x8-2fh9 msgpack5 (npm) Fixed in 6.1.0 Advisory →

Timeline

  1. 2026-10-08 Threatist record created from CVE-2026-107300
  2. 2026-10-08 Alias added: GHSA-5x5g-h9x8-2fh9

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-2026-69599 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
  • TI-2026-69600 Reserved byte in msgpack5 causes unbounded stream buffering 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