CVE-2026-57585
MessagePack: Out-of-bounds read/crash on Unpacker reuse after caught error
Description
MessagePack is the serializer implementation for Python msgpack.org. Prior to 1.2.1, there is an Out-of-bounds read/crash on Unpacker reuse after a caught error, potentially leading to a DoS attack. If the Unpacker is used repeatedly after an error occurs, the process may crash with a SEGV. This issue has been fixed in version 1.2.1.
INFO
Published Date :
June 30, 2026, 10:16 p.m.
Last Modified :
July 2, 2026, 6:43 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
Affected Products
The following products are affected by CVE-2026-57585
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | HIGH | MITRE-CVE | ||||
| CVSS 3.1 | HIGH | [email protected] |
Solution
- Update MessagePack to version 1.2.1 or later.
- Avoid Unpacker reuse after encountering an error.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-57585.
| URL | Resource |
|---|---|
| https://github.com/msgpack/msgpack-python/commit/2c56ddb5d0025ed481d962c0f5d62d19dec7476d | |
| https://github.com/msgpack/msgpack-python/security/advisories/GHSA-6v7p-g79w-8964 |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-57585 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-57585
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-57585 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-57585 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jul. 01, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2026-57585', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'yes'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-07-01T14:54:21.105642Z'} -
New CVE Received by [email protected]
Jun. 30, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'msgpack', 'product': 'msgpack-python', 'versions': [{'status': 'affected', 'version': '< 1.2.1'}]}] Added Description MessagePack is the serializer implementation for Python msgpack.org. Prior to 1.2.1, there is an Out-of-bounds read/crash on Unpacker reuse after a caught error, potentially leading to a DoS attack. If the Unpacker is used repeatedly after an error occurs, the process may crash with a SEGV. This issue has been fixed in version 1.2.1. Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Added CWE CWE-416 Added Reference https://github.com/msgpack/msgpack-python/commit/2c56ddb5d0025ed481d962c0f5d62d19dec7476d Added Reference https://github.com/msgpack/msgpack-python/security/advisories/GHSA-6v7p-g79w-8964