MessagePack for Python: Out-of-bounds read / crash on Unpacker reuse after a caught error
Key facts
- Attack vector
- —
- Privileges required
- —
- User interaction
- —
- Attack complexity
- —
- Impact type
- —
- Confidentiality · integrity · availability
- —
- Fix status
- Fixed
No CVSS vector from any source. Fix status from GitHub.
Summary
### Impact If the Unpacker is used repeatedly after an error occurs, the process may crash with a SEGV. If the Unpacker is used repeatedly to unpack untrusted input from external sources, it may be vulnerable to a DoS attack. ### Patches v1.2.1 ### Workarounds Users should create a new Unpacker instead of reusing the same Unpacker after an error occurs. Applying the above patch can prevent SEGV, but reusing the Streaming Unpacker after it has encountered an error will not yield correct data. If an error occurs during Streaming Unpacking, the Stream and Streaming Unpacker should be discarded. Therefore, this is not just a workaround but the correct solution. The above patch only prevents crashes from incorrect usage.
Why it matters now
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| — | msgpack (PyPI) | before 1.2.1 | 1.2.1 | Patch available | GHSA-6v7p-g79w-8964 |
- msgpack (PyPI) Vendor— Affected before 1.2.1 Fixed in 1.2.1 Patch available GHSA-6v7p-g79w-8964
Remediation
- Fix · GHSA-6v7p-g79w-8964 msgpack (PyPI) Fixed in 1.2.1 Advisory →
Timeline
- 2026-10-03 Threatist record created from GHSA-6v7p-g79w-8964
References
Sources
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences