TI-2026-69605 Aliases CVE-2026-107302 GHSA-8f34-f56x-9xph

Truncated map32 headers throw RangeError in msgpack5 decoder

LOW 39CWE-125Published 2026-10-08 · Updated 2026-10-19

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-125 and the CVSS impact.

Summary

msgpack5 from 4.1.0 before 6.1.0 is affected. Its decoder reads the four-byte length of a map32 value before checking that the complete five-byte header is present, which is an out-of-bounds read (CWE-125). A remote attacker can send a truncated map32 header, causing the decoder to throw RangeError instead of IncompleteBufferError, which can terminate a request, stream or worker in applications that wait for more bytes.

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 decoder reads the four-byte length of a map32 value before validating that the complete five-byte header is available. A truncated map32 header therefore causes a checked out-of-bounds buffer read and throws RangeError instead of IncompleteBufferError, which can unexpectedly terminate a request, stream, or worker in applications that wait for additional bytes after IncompleteBufferError. There is no adjacent-memory disclosure because the buffer implementation checks bounds. This issue is fixed in version 6.1.0.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV

EPSS 0.0052 44th percentileScored 2026-11-07

Fix Fixed msgpack5 (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

Vendor	Product	Affected versions	Fixed in	Status	Source
mcollina	msgpack5	>= 4.1.0. < 6.1.0	—	No fix listed	CNA
—	msgpack5 (npm)	4.1.0 to before 6.1.0	6.1.0	Patch available	GHSA-8f34-f56x-9xph

msgpack5 Vendormcollina Affected >= 4.1.0. < 6.1.0 Fixed in — No fix listed CNA
msgpack5 (npm) Vendor— Affected 4.1.0 to before 6.1.0 Fixed in 6.1.0 Patch available GHSA-8f34-f56x-9xph

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 · GHSA-8f34-f56x-9xph msgpack5 (npm) Fixed in 6.1.0 Advisory →

Timeline

2026-10-08 Threatist record created from CVE-2026-107302
2026-10-08 Alias added: GHSA-8f34-f56x-9xph
2026-10-20 Affected versions changed · CNA
2026-10-20 Affected versions changed · GHSA-8f34-f56x-9xph
2026-10-20 1 new reference · GHSA-8f34-f56x-9xph

References

Advisory 1

https://nvd.nist.gov/vuln/detail/CVE-2026-107302

Other 4

TI-2026-76780 Command injection in mcollina mcp-ripgrep Advanced Search Tool CVSS 4.0MEDIUM 4.8
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
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