CVE-2026-32284 Denial of service in github.com/shamaton/msgpack
A denial of service vulnerability in the Go msgpack library allows attackers to cause a runtime panic via truncated fixext data.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-32284?
CVE-2026-32284 is a high-severity denial of service vulnerability in github.com/shamaton/msgpack, published on 26 Mar 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
The msgpack decoder fails to properly validate the input buffer length when processing truncated fixext data (format codes 0xd4-0xd8). This can lead to an out-of-bounds read and a runtime panic, allowing a denial of service attack.
Weakness: CWE-125
Which versions are affected by CVE-2026-32284?
7 open source packages ship an affected version, including github.com/shamaton/msgpack/v2, github.com/shamaton/msgpack and github.com/shamaton/msgpack/v3. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
github.com/shamaton/msgpack/v2 Go | All versions to 2.4.0 | None |
github.com/shamaton/msgpack/v2 Go | All versions to 2.4.0 | None |
github.com/shamaton/msgpack/v2 Go | All versions | 2.4.1 |
github.com/shamaton/msgpack Go | All versions | None |
github.com/shamaton/msgpack/v3 Go | All versions to 3.1.0 | None |
github.com/shamaton/msgpack/v3 Go | All versions to 3.1.0 | None |
1 more packages
github.com/shamaton/msgpack/v3 Go | All versions | 3.1.1 |
Products include Shamaton Msgpack.
How do I fix CVE-2026-32284?
Upgrade github.com/shamaton/msgpack/v2 to 2.4.1 or later.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-32284 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-32284 exists.
Sources
Also known as GHSA-h9q6-hc68-35rp, GO-2026-4513.