msgpack5 is a msgpack v5 implementation for node.js and the browser. Prior to 6.1.0, the streaming decoder reparses an incomplete array or map from the beginning whenever another chunk arrives. A remote peer can split one valid MessagePack container across many small chunks, causing completed elements to be decoded repeatedly, producing quadratic CPU use and blocking the event loop. This issue is fixed in version 6.1.0.
CVE-2026-107297
“—” beside the score: it is equal to the CVSS score beside it.
Score 5.9 from GitHub Security Advisory (severity: MODERATE) published 2026-10-08. A secondary CVSS source baseline 5.9; sources differ by 0.0.
Also known asEUVD-2026-95108 (ENISA EUVD) · GHSA-gcx5-hxj7-gpqq (GitHub Security Advisories)Source: ENISA EUVD
- Lower severity and no public exploit yet
A fix is available — apply it.
- CVSS v3
- 5.9
- EG Score
- 5.9MEDIUMhigh confidence
- EG Risk
- 27EG Risk 27/100
EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.
How it’s computed (value × EchelonGraph’s weight)Severity59% × 45%Impact severity (EG Severity): CVSS 5.9 of 10. Never the KEV-floored or EPSS-lifted EG Score.Exploitation0.4% × 40%FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.Automatability0% × 15%CISA's SSVC Automatable value: no (Vulnrichment).SSVC (CISA's decision table, applied by EchelonGraph): Track at every mission impact level.Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.Action: A fix is available. Apply it within your standard update timelines. - EPSS PROB
- 0.4%
- EPSS %ILE
- 32nd
- KEV
- Not listed
What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)
The EG score (5.9): severity, escalated by confirmed exploitation. This CVE's 5.9 is its impact severity (EG Severity), not escalated.
- EG Severity
- 5.9 MEDIUMCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
- EG Likelihood
- 0.4% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-31). FIRST's exploitation probability, not an EchelonGraph model.
- Confirmed exploitation
- None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
- EG Priority
- SSVC Track at medium mission impactTrack at every mission impact level.CISA BOD 26-04: 60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.Each input and its source, and whom BOD 26-04 binds: the SSVC and BOD 26-04 blocks below.
SSVC (CISA's decision table, applied by EchelonGraph)Track at every mission impact level.
A fix is available. Apply it within your standard update timelines.
Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table
BOD 26-04 (CISA's remediation timeline, Table 1)60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.
The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it
Published
October 8, 2026
Last Modified
October 8, 2026
Advisory Details (3)
Auto-updated Oct 8, 2026Quadratic parsing in the streaming decoder · Advisory · mcollina/msgpack5 · GitHub
https://github.com/mcollina/msgpack5/security/advisories/GHSA-gcx5-hxj7-gpqqv6.1.0
Patch available: mcollina/msgpack5 v6.1.0
https://github.com/mcollina/msgpack5/releases/tag/v6.1.0commit e4827641d310 (mcollina/msgpack5)
Patch available: mcollina/msgpack5 v6.1.0 (contains commit e4827641d310)
https://github.com/mcollina/msgpack5/commit/e4827641d3105e295cbbd56e9c5389978547eab4Vendor Advisories for CVE-2026-107297(2)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
Patch Availability(1)
| Vendor / Ecosystem | Fix (by version range) / Patch | Released | Source |
|---|---|---|---|
| npm | msgpack5 @ 6.1.0 (fixes < 6.1.0) | — | ghsa |
Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.
Affected Packages
(1 across 1 ecosystem)
npm(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| msgpack5 | — |
| — |
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 10× in last 7d / 41× in last 30d)
Each row is a time one of our pipelines fetched, updated or re-scored this CVE. 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. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.
- 2026-11-02 16:43 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
- 2026-11-01 16:33 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
- 2026-11-01 08:00 UTCEG score recompute
- 2026-11-01 08:00 UTCGHSA enrichmentGHSA-gcx5-hxj7-gpqq · GitHub severity MODERATE · GitHub CVSS 5.9
- 2026-10-31 16:31 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
- 2026-10-31 11:25 UTCOSV refresh
- 2026-10-30 16:33 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
- 2026-10-29 16:32 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
- 2026-10-28 16:31 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
- 2026-10-27 16:31 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
- 2026-10-26 16:30 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
- 2026-10-25 16:32 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
- 2026-10-25 14:54 UTCEG score recompute
- 2026-10-24 16:32 UTCEPSS rescoreEPSS 0.4% · 31st percentile
- 2026-10-23 16:31 UTCEPSS rescoreEPSS 0.4% · 31st percentile
- 2026-10-23 08:44 UTCEG score recompute
- 2026-10-23 08:44 UTCVendor advisory
- 2026-10-22 16:33 UTCEPSS rescoreEPSS 0.4% · 31st percentile
- 2026-10-21 16:32 UTCEPSS rescoreEPSS 0.4% · 31st percentile
- 2026-10-20 16:32 UTCEPSS rescoreEPSS 0.4% · 31st percentile
- 2026-10-19 16:31 UTCEPSS rescoreEPSS 0.4% · 31st percentile
- 2026-10-18 16:31 UTCEPSS rescoreEPSS 0.4% · 31st percentile
- 2026-10-18 05:07 UTCEG score recompute
- 2026-10-17 16:33 UTCEPSS rescoreEPSS 0.4% · 31st percentile
- 2026-10-16 16:40 UTCEPSS rescoreEPSS 0.4% · 31st percentile
Show 16 moreShow fewer
- 2026-10-15 16:31 UTCEPSS rescoreEPSS 0.4% · 31st percentile
- 2026-10-14 16:32 UTCEPSS rescoreEPSS 0.4% · 31st percentile
- 2026-10-13 16:33 UTCEPSS rescoreEPSS 0.4% · 31st percentile
- 2026-10-12 16:38 UTCEG score recompute
- 2026-10-12 16:33 UTCEPSS rescoreEPSS 0.4% · 31st percentile
- 2026-10-11 20:14 UTCEG score recompute
- 2026-10-11 17:54 UTCEG score recompute
- 2026-10-11 17:54 UTCVendor advisory
- 2026-10-11 15:00 UTCEG score recompute
- 2026-10-11 13:47 UTCEPSS rescoreEPSS 0.4% · 30th percentile
- 2026-10-10 19:59 UTCEPSS rescoreEPSS 0.4% · 30th percentile
- 2026-10-10 18:38 UTCEG score recompute
- 2026-10-09 20:06 UTCEPSS rescoreEPSS 0.4% · 30th percentile
- 2026-10-08 17:25 UTCEG score recompute
- 2026-10-08 17:15 UTCEG score recomputeFirst assessed: 5.9 MEDIUM
- 2026-10-08 17:14 UTCMITRE cvelistV5first tracked
Related CVEs(same product + same CWE)
Same product
7 shownnpm:msgpack5
Frequently asked(5)
What is CVE-2026-107297?
When was the CVE record for CVE-2026-107297 published?
Is CVE-2026-107297 actively exploited?
What is the CVSS score of CVE-2026-107297?
How do I remediate CVE-2026-107297?
Dependency Blast Radius
See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-107297
Is Your Infrastructure Affected by CVE-2026-107297?
EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.