Quick answers
- Is CVE-2026-107298 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-107298 being exploited in the wild.
- How severe is CVE-2026-107298?
- Medium severity, with a CVSS score of 5.3, published 8 October 2026.
- Which products and versions are affected?
- Mcollina Msgpack5 < 6.1.0; msgpack5 (npm) < 6.1.0, SEMVER:introduced=0,fixed=6.1.0.
- Is there a fix for CVE-2026-107298?
- Yes. msgpack5 (npm): upgrade to 6.1.0 or later. Until then: Reject deeply nested input before decoding, isolate decoding in a worker thread, or enforce a trusted schema with a bounded nesting depth. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
- How is CVE-2026-107298 attacked?
- It is attacked over the network, in a software library.
- Am I affected by CVE-2026-107298?
- Check whether you run Mcollina Msgpack5 or msgpack5 (npm) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
How to fix
- msgpack5 (npm): upgrade to 6.1.0 or later
npm install msgpack5@6.1.0
Reject deeply nested input before decoding, isolate decoding in a worker thread, or enforce a trusted schema with a bounded nesting depth.
Technical details
The decoder lacks a nesting depth limit for arrays and maps, allowing uncontrolled recursion when processing deeply nested containers (CWE-674). An unauthenticated attacker over the network can provide malicious MessagePack input to trigger stack exhaustion. The fix implements a default maximum nesting depth of 100 and allows configuration via the maxDepth option.
Affected products
- mcollina msgpack5 < 6.1.0
Identifiers
- CVE-2026-107298
- GHSA-24ch-f2g6-9hhh
Timeline
- 2026-09-26: disclosed
- 2026-10-08: advisory