CVE-2026-107299: msgpack5: Reserved byte can cause unbounded stream buffering
mcollina · msgpack5
Affected: mcollina msgpack5 · Exploitation: unlikely (under 1%)
Not in CyberSIXT coverage yet: no article names this CVE. This page shows the public record.
Higher than 33% of scored CVEs
DescriptionCVE.org
msgpack5 is a msgpack v5 implementation for node.js and the browser. Prior to 6.1.0, the streaming decoder treats the reserved MessagePack byte 0xc1 as incomplete input instead of invalid input. When 0xc1 begins a stream, subsequent data remains buffered while the decoder waits for bytes that cannot make the value valid, allowing a remote peer to exhaust memory. This issue is fixed in version 6.1.0.
Affected products1
From the CVE record. A product or version that is not listed is unknown, not unaffected.
- mcollina · msgpack5< 6.1.0
On the Atlas
Every published CVE is on the CyberSIXT Atlas, grouped by weakness, vendor and month.
- Exploitation
- Unlikely (under 1%). EPSS under 1%, or no score yet.
- CISA KEV
- Not listed
- Public check
- No public nuclei template
- Vendor
- mcollina
- Published
- October 2026
CoverageNo articles yet
No CyberSIXT article names CVE-2026-107299 yet, so there is no coverage timeline, action brief or change log for it. Everything on this page comes from the public CVE record, CISA KEV, EPSS and the nuclei template index. Search the archive or see the CVEs in the news.