CVE-2026-107302msgpack5: Truncated map32 headers throw an unexpected error
Updated under an hour ago ()
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It affects mcollina msgpack5. Add what you run to find out whether that includes you.
EPSS puts the chance of exploitation in the next 30 days at 0.43%, higher than 35% of scored CVEs.
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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.
- CVSS
- 7.5 HIGH (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- Weakness (CWE)
- CWE-125
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- 0.43% (percentile 35)
- Assigned by
- GitHub_M
- NVD analysis
- Deferred
- Record last updated
- Oct 8, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
mcollina msgpack5 mcollina:msgpack5 (from the name) | before 6.1.0 | CNA record |
References
- https://github.com/mcollina/msgpack5/security/advisories/GHSA-8f34-f56x-9xphx-refsource-confirm
- https://github.com/mcollina/msgpack5/commit/15443a1f2aa682a6aa37f1705ac628de5b866ad1x-refsource-misc
- https://github.com/mcollina/msgpack5/releases/tag/v6.1.0x-refsource-misc
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.