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.
CVE-2026-57585
This high-severity CVE scores 7.5 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.3%, top 80% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).
- High severity, but no confirmed exploitation yet
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 7.5
- EG Score
- 7.5(medium)
- EG Risk
- 38(Track)EG Risk 38/100SSVC: Track
EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).
How it’s computedSeverity75% × 45%Exploitation0% × 40%Automatability30% × 15%Action: Routine — remediate on your standard cadence. - EPSS PROB
- 0%
- EPSS %ILE
- 20%
- KEV
- Not listed
Published
June 30, 2026
Last Modified
July 2, 2026
Advisory Details (2)
Auto-updated Jun 30, 2026Out-of-bounds read / crash on Unpacker reuse after a caught error · Advisory · msgpack/msgpack-python · GitHub
https://github.com/msgpack/msgpack-python/security/advisories/GHSA-6v7p-g79w-8964commit 2c56ddb5d002 (msgpack/msgpack-python)
Patch available: msgpack/msgpack-python v1.2.1 (contains commit 2c56ddb5d002)
https://github.com/msgpack/msgpack-python/commit/2c56ddb5d0025ed481d962c0f5d62d19dec7476dAffected Packages
(1 across 1 ecosystem)
PyPI(1)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| msgpack | 0.5.0 ... 1.2.0rc1 (32 versions) | 1.2.1 | — |
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
All Vendor Advisories
(1)
Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.
Data Freshness Timeline
(refreshed 20× in last 7d / 61× in last 30d)
Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.
- 2026-07-28 15:37 UTCEPSS rescore
- 2026-07-28 05:12 UTCVendor advisory
- 2026-07-27 16:47 UTCEG score recompute
- 2026-07-27 16:47 UTCVendor advisory
- 2026-07-27 14:14 UTCEPSS rescore
- 2026-07-27 02:13 UTCEG score recompute
- 2026-07-27 02:13 UTCVendor advisory
- 2026-07-26 14:54 UTCEPSS rescore
- 2026-07-26 14:54 UTCEPSS rescore
- 2026-07-26 13:49 UTCEG score recompute
- 2026-07-26 13:49 UTCVendor advisory
- 2026-07-25 14:18 UTCEPSS rescore
- 2026-07-25 14:18 UTCEPSS rescore
- 2026-07-24 14:18 UTCEPSS rescore
- 2026-07-24 14:18 UTCEPSS rescore
- 2026-07-23 14:18 UTCEPSS rescore
- 2026-07-23 14:18 UTCEPSS rescore
- 2026-07-23 03:20 UTCEG score recompute
- 2026-07-22 14:08 UTCEPSS rescore
- 2026-07-22 14:08 UTCEPSS rescore
- 2026-07-21 15:25 UTCEPSS rescore
- 2026-07-20 17:08 UTCEPSS rescore
- 2026-07-19 14:31 UTCEPSS rescore
- 2026-07-19 14:31 UTCEPSS rescore
- 2026-07-19 02:29 UTCEPSS rescore
Show 36 moreShow fewer
- 2026-07-18 10:04 UTCEPSS rescore
- 2026-07-16 22:12 UTCVendor advisory
- 2026-07-16 17:03 UTCEPSS rescore
- 2026-07-16 09:49 UTCVendor advisory
- 2026-07-15 21:28 UTCVendor advisory
- 2026-07-15 16:57 UTCEPSS rescore
- 2026-07-15 16:57 UTCEPSS rescore
- 2026-07-15 09:03 UTCVendor advisory
- 2026-07-15 02:00 UTCEPSS rescore
- 2026-07-15 02:00 UTCEPSS rescore
- 2026-07-14 20:37 UTCVendor advisory
- 2026-07-14 08:13 UTCVendor advisory
- 2026-07-13 22:31 UTCEPSS rescore
- 2026-07-13 06:13 UTCEPSS rescore
- 2026-07-13 06:13 UTCEPSS rescore
- 2026-07-12 19:09 UTCVendor advisory
- 2026-07-12 06:48 UTCVendor advisory
- 2026-07-12 05:46 UTCEPSS rescore
- 2026-07-11 18:27 UTCVendor advisory
- 2026-07-11 08:27 UTCEPSS rescore
- 2026-07-11 08:27 UTCEPSS rescore
- 2026-07-09 19:10 UTCEPSS rescore
- 2026-07-09 19:10 UTCEPSS rescore
- 2026-07-07 13:46 UTCEPSS rescore
- 2026-07-07 13:46 UTCEPSS rescore
- 2026-07-06 16:27 UTCEPSS rescore
- 2026-07-06 16:27 UTCEPSS rescore
- 2026-07-06 02:23 UTCEPSS rescore
- 2026-07-06 02:23 UTCEPSS rescore
- 2026-07-05 02:31 UTCEPSS rescore
- 2026-07-05 02:30 UTCEPSS rescore
- 2026-07-04 06:31 UTCEPSS rescore
- 2026-07-04 06:31 UTCEPSS rescore
- 2026-07-01 15:07 UTCEPSS rescore
- 2026-06-30 22:34 UTCEG score recompute
- 2026-06-30 22:33 UTCNVD updatefirst tracked
Frequently asked(5)
What is CVE-2026-57585?
When was CVE-2026-57585 disclosed?
Is CVE-2026-57585 actively exploited?
What is the CVSS score of CVE-2026-57585?
How do I remediate CVE-2026-57585?
Dependency Blast Radius
See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-57585
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