tsParticles is a TypeScript library for creating highly customizable particle animations. Prior to 4.3.2, the HTTP mode of @tsparticles/mcp-server reuses one stateful StreamableHTTPServerTransport for every client. An unauthenticated client that sends the first initialize request without an mcp-session-id claims the shared transport state, causing later independent clients to receive Server already initialized and preventing them from establishing sessions until the process restarts. The first client's session remains functional. This issue is fixed in version 4.3.2.
CVE-2026-76893
MEDIUMPre-NVD 6.96.9Trending — 4 sources updated this weekElevatedEG-KEV Tier 3: ElevatedEG-KEV is EchelonGraph's own tiering of exploitation signals from CISA KEV, CISA's SSVC data (Vulnrichment), ransomware data, public exploit-code references and EPSS.Tier 3 is not evidence of exploitation. It means public exploit code is referenced, or CISA's SSVC data says "public PoC", or EPSS ranks the CVE in the top 5%.Signals for this CVE: CISA's SSVC exploitation value: public PoC.EchelonGraph confidence 38%: a heuristic from the tier and the number of signals, not a measured probability.
EchelonGraph scoreMEDIUM confidence
“—” beside the score: it is equal to the CVSS score beside it.
This medium-severity CVE scores 6.9 under the CNA's CVSS (NVD's own analysis pending). EPSS exploit probability: 0.3% (21st percentile of EPSS-scored CVEs). No GitHub Security Advisory CVSS is on record for this CVE.
Triggered by: Headline CVSS from the CNA's CVSS
Sources: the CNA's CVSS, EPSS
Also known asEUVD-2026-117156 (ENISA EUVD)Source: ENISA EUVD
6.9EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines at low or medium mission impact and sooner than that at high (the SSVC decision on this page).
- CISA's Vulnrichment rates exploitation as PoC; EchelonGraph holds no exploit-code reference for it
CISA-KEV: Not listedEPSS PROB: 0.3%CVSS: 6.9Exploit: No code on recordExposed services: Not assessed
The CVE record names the fixed release — apply it.
- CVSS v3
- 6.9
- EG Score
- 6.9MEDIUMmedium confidence
- EG Risk
- 62EG Risk 62/100
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)Severity69% × 45%Impact severity (EG Severity): CVSS 6.9 of 10. Never the KEV-floored or EPSS-lifted EG Score.Exploitation40% × 40%EchelonGraph's fixed weight for EG-KEV Tier 3 (Elevated): a constant, not a probability.Automatability100% × 15%CISA's SSVC Automatable value: yes (Vulnrichment).SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Attend at high (mission-essential systems).Exploitation public PoC (CISA Vulnrichment) · Automatable yes (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: The CVE record names the fixed release. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high. - EPSS PROB
- 0.3%
- EPSS %ILE
- 21st
- 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 (6.9): severity, escalated by confirmed exploitation. This CVE's 6.9 is its impact severity (EG Severity), not escalated.
- EG Severity
- 6.9 MEDIUMCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.the CNA's CVSS · CVSS v3.0 or v3.1
- EG Likelihood
- 0.3% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-11-05). 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 low or medium mission impact; Attend at high (mission-essential systems).CISA BOD 26-04: 14 days if the affected system is publicly exposed; 60 days 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 low or medium mission impact; Attend at high (mission-essential systems).
The CVE record names the fixed release. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
Exploitation public PoC (CISA Vulnrichment) · Automatable yes (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)14 days if the affected system is publicly exposed; 60 days if it is not.
The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable yes (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
November 4, 2026
Last Modified
November 5, 2026
Advisory Details (3)
Auto-updated Nov 4, 2026🔬 Proof of concept available. Fix named in the CVE record. Sources: github, github_commit, github_pr.
GitHub advisoryMentions a patch (unverified)🟡 PoC Available
A single anonymous MCP session can monopolize HTTP mode and deny new clients · Advisory · tsparticles/tsparticles · GitHub
https://github.com/tsparticles/tsparticles/security/advisories/GHSA-h7c4-q426-7jh9GitHub pull request
4.3.2
Fix merged in tsparticles/tsparticles PR #5888 on 2026-07-10 — awaiting tagged release
https://github.com/tsparticles/tsparticles/pull/5888GitHub commit
commit d3b5672bd61b (tsparticles/tsparticles)
Fix landed in tsparticles/tsparticles commit d3b5672bd61b — awaiting tagged release
https://github.com/tsparticles/tsparticles/commit/d3b5672bd61bb847abfa21193c34eabf7aba6896Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 7× in last 7d / 7× 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.
- 2026-11-05 21:26 UTCEG score recompute
- 2026-11-05 20:28 UTCEG score recompute
- 2026-11-05 16:38 UTCEPSS rescoreEPSS 0.3% · 21st percentile
- 2026-11-04 23:03 UTCENISA EUVD ID recordedEUVD-2026-117156 · Source: ENISA EUVD
- 2026-11-04 22:30 UTCEG score recompute
- 2026-11-04 22:17 UTCEG score recomputeFirst assessed: 6.9 MEDIUM
- 2026-11-04 22:15 UTCMITRE cvelistV5first tracked
Related CVEs(same CWE)
Frequently asked(5)
What is CVE-2026-76893?
CVE-2026-76893 is a medium-severity vulnerability; its CVE record was published on November 4, 2026. tsParticles is a TypeScript library for creating highly customizable particle animations. Prior to 4.3.2, the HTTP mode of @tsparticles/mcp-server reuses one stateful StreamableHTTPServerTransport for every client. An unauthenticated client that sends the first initialize request without an…
When was the CVE record for CVE-2026-76893 published?
The CVE record for CVE-2026-76893 was published on November 4, 2026. That is the record's publication date; the vulnerability itself may have been made public earlier. EchelonGraph's copy of the record carries a last-modified date of November 5, 2026; the record at its source may have been updated since.
Is CVE-2026-76893 actively exploited?
CVE-2026-76893 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.3% probability of exploitation in the next 30 days (21st percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-76893?
CVE-2026-76893 has a CVSS base score of 6.9 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-76893?
The CVE record for CVE-2026-76893 names the fix: "This issue is fixed in version 4.3.2."
Dependency Blast Radius
Explore the affected products and dependency analysis for CVE-2026-76893
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