Answer in brief
CVE-2026-57585 records a High severity (CVSS 7.5) vulnerability in MessagePack for Python: Out-of-bounds read / crash on Unpacker reuse after a caught error. The current sources do not mark it as known exploited. The current feed maps msgpack (pip), msgpack (pypi). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 7.5. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps msgpack (pip), msgpack (pypi). Check affected ranges and fixed versions before updating.
| Product | Affected versions | Fixed versions |
|---|---|---|
| cpe:2.3:a:msgpack:messagepack:*:*:*:*:*:python:*:* | Not reported | Not reported |
| Package | Affected range | Fixed version |
|---|---|---|
| msgpackpip | <=1.2.0 | 1.2.1 |
| msgpackpypi | >=0 <1.2.1 | 1.2.1 |
Published upstream
Jun 19, 2026
Evidence: source:ghsa:source_dates:source-dates:recordSource modified
Sep 10, 2026
Evidence: source:ghsa:source_dates:source-dates:recordFirst seen by HOL
Jun 19, 2026
### 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.
Quoted source text, attributed separately from HOL analysis.