CVE-2026-57585: CWE-416: Use After Free in msgpack msgpack-python
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.
AI Analysis
Technical Summary
The vulnerability identified as CVE-2026-57585 affects msgpack-python versions before 1.2.1. It is a use-after-free condition (CWE-416) triggered by reusing the Unpacker object after an error has occurred during unpacking. This causes an out-of-bounds read that can crash the process with a segmentation fault (SEGV), potentially enabling denial-of-service attacks. The issue is resolved in msgpack-python version 1.2.1.
Potential Impact
Exploitation of this vulnerability can cause the affected process to crash, resulting in denial of service. There is no indication of confidentiality or integrity impact. No known exploits are reported in the wild at this time.
Mitigation Recommendations
Upgrade msgpack-python to version 1.2.1 or later, where this vulnerability has been fixed. No other mitigation or workaround is indicated.
CVE-2026-57585: CWE-416: Use After Free in msgpack msgpack-python
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.
CVSS v3.1
Score 7.5high
Affected software
Run on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The vulnerability identified as CVE-2026-57585 affects msgpack-python versions before 1.2.1. It is a use-after-free condition (CWE-416) triggered by reusing the Unpacker object after an error has occurred during unpacking. This causes an out-of-bounds read that can crash the process with a segmentation fault (SEGV), potentially enabling denial-of-service attacks. The issue is resolved in msgpack-python version 1.2.1.
Potential Impact
Exploitation of this vulnerability can cause the affected process to crash, resulting in denial of service. There is no indication of confidentiality or integrity impact. No known exploits are reported in the wild at this time.
Mitigation Recommendations
Upgrade msgpack-python to version 1.2.1 or later, where this vulnerability has been fixed. No other mitigation or workaround is indicated.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-06-24T18:49:56.209Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a443df227e9c79719767792
Added to database: 06/30/2026, 22:06:42 UTC
Last enriched: 07/08/2026, 12:44:01 UTC
Last updated: 08/13/2026, 12:41:11 UTC
Views: 73
Community Reviews
0 reviewsCrowdsource mitigation strategies, share intel context, and vote on the most helpful responses. Sign in to add your voice and help keep defenders ahead.
Want to contribute mitigation steps or threat intel context? Sign in or create an account to join the community discussion.
Actions
Updates to AI analysis require Pro Console access. Upgrade inside Console → Billing.
Need more coverage?
Upgrade to Pro Console for AI refresh and higher limits.
For incident response and remediation, OffSeq services can help resolve threats faster.
Latest Threats
Check if your credentials are on the dark web
Instant breach scanning across billions of leaked records. Free tier available.