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TI-2026-41435 Aliases CVE-2026-57585

MessagePack: Out-of-bounds read/crash on Unpacker reuse after caught error

Priority LOW 39CWE-416Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
Denial of service
Confidentiality · integrity · availability
None · None · High
Fix status
Partial Red Hat: 2 fixed, 2 without a fix

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat. Impact type from CWE-416 and the CVSS impact.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00488 42nd percentileScored 2026-11-07
Fix Partial msgpack-python (msgpack): 1.2.1Red Hat: 5 advisoriesRed Hat: 2 fixed, 2 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
Yes
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
msgpackmsgpack-pythonbefore 1.2.11.2.1Patch availableCNA
  • msgpack-python Vendormsgpack Affected before 1.2.1 Fixed in 1.2.1 Patch available CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:msgpack:messagepack:*:*:*:*:*:python:*:*before 1.2.1Vulnerablemsgpack
  • cpe:2.3:a:msgpack:messagepack:*:*:*:*:*:python:*:* Versions before 1.2.1 Vulnerable ·msgpack

Remediation

  • Fix · CNA msgpack-python (msgpack) Fixed in 1.2.1

Red Hat 5 advisories

  • RHSA-2026:73930 Released 2026-09-30 · Red Hat rating Important
    Red Hat AI Inference Server 3.2.2 (rocm)
    • Red Hat AI Inference Server 3.2 registry.redhat.io/rhaiis/vllm-rocm-rhel9
  • RHSA-2026:73929 Released 2026-09-30 · Red Hat rating Important
    Red Hat AI Inference Server 3.2.2 (cuda)
    • Red Hat AI Inference Server 3.2 registry.redhat.io/rhaiis/vllm-cuda-rhel9
  • RHSA-2026:70995 Released 2026-09-23 · Red Hat rating Important
    Red Hat AI Inference 3.4.5 (rocm)
    • Red Hat AI Inference Server 3.4 registry.redhat.io/rhaii/vllm-rocm-rhel9
Show 2 more Red Hat advisories
  • RHSA-2026:70979 Released 2026-09-23 · Red Hat rating Important
    Red Hat AI Inference 3.4.5 (cuda)
    • Red Hat AI Inference Server 3.4 registry.redhat.io/rhaii/vllm-cuda-rhel9
  • RHSA-2026:70965 Released 2026-09-23 · Red Hat rating Important
    Red Hat AI Inference 3.4.5 (cpu)
    • Red Hat AI Inference Server 3.4 registry.redhat.io/rhaii/vllm-cpu-rhel9

Vendor assessments

Red Hat

Red Hat rating: Important. Red Hat's page for this CVE →

ProductStatusPlan or fix
Red Hat Enterprise Linux 10AffectedNo fix yet
Red Hat Enterprise Linux 9AffectedNo fix yet
Red Hat AI Inference Server 3.2Fixed RHSA-2026:73929, RHSA-2026:73930
Red Hat AI Inference Server 3.4Fixed RHSA-2026:70965, RHSA-2026:70979, RHSA-2026:70995
Not affected: 14 products
  • Pen Drive Powered by Red Hat Lightspeed
  • Red Hat AI Inference Server
  • Red Hat Ansible Automation Platform 2
  • Red Hat Enterprise Linux 10
  • Red Hat Enterprise Linux 8
  • Red Hat Enterprise Linux AI (RHEL AI) 3
  • Red Hat OpenShift AI (RHOAI)
  • Red Hat OpenShift Container Platform 4
  • Red Hat OpenShift Container Platform 5
  • Red Hat OpenStack Platform 16.2
  • Red Hat OpenStack Platform 17.1
  • Red Hat OpenStack Platform 18.0
  • Red Hat Quay 3
  • Red Hat Satellite 6

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-57585
  2. 2026-10-05 Affected versions changed · Red Hat
  3. 2026-10-30 Affected versions changed · Red Hat

References

Patch 1

Advisory 1

  • TI-2026-17336 Uncontrolled resource consumption in msgpack-java CVSS 3.1HIGH 7.5
  • TI-2026-39368 MessagePack::Buffer#clear Use-After-Free that Enables Cross-Buffer Disclosure CVSS 4.0LOW 2.1

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences