{"id":"CVE-2026-57585","title":"msgpack: MessagePack for Python: Denial of Service via Unpacker reuse after error (CVE-2026-57585)","summary":"A flaw was found in MessagePack for Python, a serializer implementation. This vulnerability, categorized as a Use-After-Free (CWE-416), occurs when the Unpacker component is reused after an error. A remote attacker could exploit this by re…","severity":"high","cvss":7.5,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","cvssSource":"vendor","cwe":"CWE-125","vendor":"Red Hat","product":"Red Hat AI Inference Server 3.4","affected":["ai_inference_server 3.4"],"patched":["ai_inference_server 3.4"],"published":"2026-06-30","updated":"2026-09-24","sourceUpdated":"2026-09-24T05:56:14+00:00","source":"CSAF","sourceUrl":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-57585.json","references":[{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-57585.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-57585"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2496020"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-57585"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-57585"},{"url":"https://github.com/msgpack/msgpack-python/commit/2c56ddb5d0025ed481d962c0f5d62d19dec7476d"},{"url":"https://github.com/msgpack/msgpack-python/security/advisories/GHSA-6v7p-g79w-8964"},{"url":"https://access.redhat.com/errata/RHSA-2026:70965"},{"url":"https://access.redhat.com/errata/RHSA-2026:70979"},{"url":"https://access.redhat.com/errata/RHSA-2026:70995"},{"url":"https://github.com/msgpack/msgpack-python"},{"url":"https://github.com/msgpack/msgpack-python/releases/tag/v1.2.1"}],"tags":["csaf","vex","red-hat","osv","pip"],"epss":0.00488,"epssPercentile":0.39332,"aliases":["GHSA-6v7p-g79w-8964","PYSEC-2026-3625"],"ecosystem":"pip","ingestedAt":"2026-07-08T18:25:46.532Z","slug":"CVE-2026-57585","body":"## Overview\n\nA flaw was found in MessagePack for Python, a serializer implementation. This vulnerability, categorized as a Use-After-Free (CWE-416), occurs when the Unpacker component is reused after an error. A remote attacker could exploit this by repeatedly providing untrusted input, leading to an out-of-bounds read and a system crash. This can result in a Denial of Service (DoS) attack.\n\n## Vendor advisories\n\n- **RHSA-2026:70965** · Red Hat · fixed in: Red Hat AI Inference Server 3.4 · released 2026-09-23 · [advisory](https://access.redhat.com/errata/RHSA-2026:70965)\n- **RHSA-2026:70979** · Red Hat · fixed in: Red Hat AI Inference Server 3.4 · released 2026-09-23 · [advisory](https://access.redhat.com/errata/RHSA-2026:70979)\n- **RHSA-2026:70995** · Red Hat · fixed in: Red Hat AI Inference Server 3.4 · released 2026-09-23 · [advisory](https://access.redhat.com/errata/RHSA-2026:70995)\n\n**msgpack: MessagePack for Python: Denial of Service via Unpacker reuse after error** — rated Important by Red Hat. Released 2026-06-30, updated 2026-09-24.\n\nFixed:\n\n- Red Hat AI Inference Server 3.4\n\nNot affected:\n\n- Pen Drive Powered by Red Hat Lightspeed\n- Red Hat AI Inference Server\n- Red Hat Ansible Automation Platform 2\n- Red Hat Enterprise Linux 10\n- Red Hat Enterprise Linux 8\n- Red Hat Enterprise Linux 9\n- Red Hat Enterprise Linux AI (RHEL AI) 3\n- Red Hat OpenShift AI (RHOAI)\n- Red Hat OpenShift Container Platform 4\n- Red Hat OpenStack Platform 16.2\n\n## Remediation\n\nFor more information visit https://access.redhat.com/errata/RHSA-2026:70965 https://access.redhat.com/errata/RHSA-2026:70965\nFor more information visit https://access.redhat.com/errata/RHSA-2026:70979 https://access.redhat.com/errata/RHSA-2026:70979\nFor more information visit https://access.redhat.com/errata/RHSA-2026:70995 https://access.redhat.com/errata/RHSA-2026:70995\n\nWorkarounds / mitigations:\n\n- To mitigate this issue, applications utilizing MessagePack for Python should be reviewed to ensure that `Unpacker` instances are not reused after an error has occurred during unpacking. Instead, a new `Unpacker` instance should be created for subsequent operations.\n\n## Package advisory (CVE-2026-57585)\n\nAffected packages:\n\n- `msgpack < 1.2.1`\n\nPatched in:\n\n- `msgpack 1.2.1`\n\nSource: https://osv.dev/vulnerability/GHSA-6v7p-g79w-8964","depth":"twilight","depthScore":41,"depthScoreParts":{"impact":41.3,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}