CVE-2026-116366

CRITICALPre-NVD 9.59.5
EchelonGraph scoreMEDIUM confidence

“—” beside the score: it is equal to the CVSS score beside it.

This critical-severity CVE scores 9.5 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 1.0% (62nd percentile of EPSS-scored CVEs). No GitHub Security Advisory CVSS is on record for this CVE.

Triggered by: Headline CVSS from a secondary CVSS source
Sources: EPSS, a secondary CVSS source
Elevated

Also known asEUVD-2026-113778 (ENISA EUVD) · GHSA-qhgw-ghp3-xh36 (GitHub Security Advisories)Source: ENISA EUVD

9.5EG
EchelonGraph verdictPlan mitigationNo fix is confirmed yet: check the vendor's advisory for a fixed release; until one is applied, restrict network exposure of the affected system or apply the vendor's mitigation on your normal schedule (the SSVC decision on this page).
  • Public exploit or proof-of-concept code is available
CISA-KEV: Not listedEPSS PROB: 1.0%CVSS: 9.5Exploit: Public PoCExposed services: Not assessed

No fix is confirmed yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for the fix.

The CVE record's CNA (ClickHouse, Inc.) lists ClickHouse versions 26.3 up to but not including 26.3.62.3-lts, 26.8 up to but not including 26.8.36.3-lts, 26.9 up to but not including 26.9.27.3-stable and 26.10 up to but not including 26.10.3.7-stable; ClickHouse Cloud versions 25.12 up to but not including 25.12.1.1713, 26.2 up to but not including 26.2.1.835, 26.4 up to but not including 26.4.1.2704, 26.6 up to but not including 26.6.1.2439 and 2 more ranges as affected. No release containing a fix is confirmed on record.

An issue has been discovered in ClickHouse Server that, under certain conditions, could allow an unauthenticated user with network access to execute arbitrary code on the ClickHouse Server.

CVSS
9.5
EG Score
9.5CRITICALmedium confidence
EG Risk
59
EG Risk 59/100

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)
Severity95% × 45%
Impact severity (EG Severity): CVSS 9.5 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.
Automatability0% × 15%
CISA's SSVC Automatable value: no (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Track* at high (mission-essential systems).
Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (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: No fix is confirmed yet. Check the vendor's advisory for a fixed release; until one is applied, restrict network exposure of the affected system or apply the vendor's mitigation on your normal schedule.
EPSS PROB
1.0%
EPSS %ILE
62nd
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 (9.5): severity, escalated by confirmed exploitation. This CVE's 9.5 is its impact severity (EG Severity), not escalated.

EG Severity
9.5 CRITICALCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.a secondary CVSS source
EG Likelihood
1.0% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-11-12). 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; Track* at high (mission-essential systems).CISA BOD 26-04: 14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.No released fix is confirmed on this page, but CISA's timeline does not wait for a fix's release: it starts when an agency identifies the flaw on an asset and updates the CDM Agency and Federal Dashboard, and the directive counts patching, decommissioning the system or another action as remediation. Until a fixed release is applied, mitigate as this page's verdict says. In the directive's words, “Fix on system upgrade” means that, “unless conditions change”, the vulnerability “should be remediated the next time the vulnerable asset receives a scheduled major upgrade or rebuild”: its timelines are “dynamic as facts change”, and a KEV listing shortens them.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; Track* at high (mission-essential systems).

No fix is confirmed yet. Check the vendor's advisory for a fixed release; until one is applied, restrict network exposure of the affected system or apply the vendor's mitigation on your normal schedule.

Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (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; Fix on system upgrade if it is not.

No released fix is confirmed on this page, but CISA's timeline does not wait for a fix's release: it starts when an agency identifies the flaw on an asset and updates the CDM Agency and Federal Dashboard, and the directive counts patching, decommissioning the system or another action as remediation. Until a fixed release is applied, mitigate as this page's verdict says. In the directive's words, “Fix on system upgrade” means that, “unless conditions change”, the vulnerability “should be remediated the next time the vulnerable asset receives a scheduled major upgrade or rebuild”: its timelines are “dynamic as facts change”, and a KEV listing shortens them.

The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA Vulnrichment) · Technical impact total (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 30, 2026

Last Modified

October 30, 2026

Advisory Details (2)

Auto-updated Oct 30, 2026
No fix on record yet.
Web page

Security changelog - ClickHouse Documentation

https://clickhouse.com/docs/resources/changelogs/security-changelog
Web page

ClickHouse/SECURITY.md at master · ClickHouse/ClickHouse · GitHub

https://github.com/ClickHouse/ClickHouse/blob/master/SECURITY.md

Vendor Advisories for CVE-2026-116366(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Affected Packages

(1 across 1 ecosystem)
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
clickhouse18.16.1+ds-7.3, 18.16.1+ds-7.4
  • every version on: no fix on record
—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 14× in last 7d / 33× 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 its CVE.org record (CNA or CISA ADP). An arrow marks a change the record states ("CVSS → 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). "EchelonGraph re-scored" is our own recompute of this CVE's score, not an update from a source, and is not counted in the refreshes above. Most recent first.

  1. 2026-11-13 06:15 UTCEchelonGraph re-scored
  2. 2026-11-13 06:15 UTCGHSA enrichmentGHSA-qhgw-ghp3-xh36 · GitHub severity CRITICAL
  3. 2026-11-12 16:33 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  4. 2026-11-12 04:27 UTCEchelonGraph re-scored
  5. 2026-11-12 04:27 UTCGHSA enrichmentGHSA-qhgw-ghp3-xh36 · GitHub severity CRITICAL
  6. 2026-11-11 16:38 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  7. 2026-11-11 02:40 UTCEchelonGraph re-scored
  8. 2026-11-11 02:40 UTCGHSA enrichmentGHSA-qhgw-ghp3-xh36 · GitHub severity CRITICAL
  9. 2026-11-10 16:42 UTCEPSS rescoreEPSS 1.0% · 61st percentile
  10. 2026-11-10 04:54 UTCEchelonGraph re-scored
  11. 2026-11-10 04:54 UTCGHSA enrichmentGHSA-qhgw-ghp3-xh36 · GitHub severity CRITICAL
  12. 2026-11-09 16:34 UTCEPSS rescoreEPSS 1.0% · 61st percentile
  13. 2026-11-09 03:09 UTCEchelonGraph re-scored
  14. 2026-11-09 03:09 UTCGHSA enrichmentGHSA-qhgw-ghp3-xh36 · GitHub severity CRITICAL
  15. 2026-11-08 16:38 UTCEPSS rescoreEPSS 1.0% · 61st percentile
  16. 2026-11-08 01:24 UTCEchelonGraph re-scored
  17. 2026-11-08 01:24 UTCGHSA enrichmentGHSA-qhgw-ghp3-xh36 · GitHub severity CRITICAL
  18. 2026-11-07 16:38 UTCEPSS rescoreEPSS 1.0% · 61st percentile
  19. 2026-11-06 23:39 UTCEchelonGraph re-scored
  20. 2026-11-06 23:39 UTCGHSA enrichmentGHSA-qhgw-ghp3-xh36 · GitHub severity CRITICAL
  21. 2026-11-06 16:36 UTCEPSS rescoreEPSS 1.0% · 61st percentile
  22. 2026-11-05 21:54 UTCEchelonGraph re-scored
  23. 2026-11-05 21:54 UTCGHSA enrichmentGHSA-qhgw-ghp3-xh36 · GitHub severity CRITICAL
  24. 2026-11-05 16:36 UTCEPSS rescoreEPSS 1.0% · 61st percentile
  25. 2026-11-04 20:09 UTCEchelonGraph re-scored
Show 25 more
  1. 2026-11-04 20:09 UTCGHSA enrichmentGHSA-qhgw-ghp3-xh36 · GitHub severity CRITICAL
  2. 2026-11-04 16:34 UTCEPSS rescoreEPSS 1.0% · 61st percentile
  3. 2026-11-03 18:23 UTCEchelonGraph re-scored
  4. 2026-11-03 18:23 UTCGHSA enrichmentGHSA-qhgw-ghp3-xh36 · GitHub severity CRITICAL
  5. 2026-11-03 16:46 UTCEPSS rescoreEPSS 1.0% · 61st percentile
  6. 2026-11-02 17:28 UTCEchelonGraph re-scored
  7. 2026-11-02 17:28 UTCGHSA enrichmentGHSA-qhgw-ghp3-xh36 · GitHub severity CRITICAL
  8. 2026-11-02 16:44 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  9. 2026-11-02 16:33 UTCGHSA enrichmentGHSA-qhgw-ghp3-xh36 · GitHub severity CRITICAL
  10. 2026-11-01 23:16 UTCEchelonGraph re-scored
  11. 2026-11-01 23:16 UTCGHSA enrichmentGHSA-qhgw-ghp3-xh36 · GitHub severity CRITICAL
  12. 2026-11-01 16:33 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  13. 2026-10-31 21:32 UTCEchelonGraph re-scored
  14. 2026-10-31 21:31 UTCGHSA enrichmentGHSA-qhgw-ghp3-xh36 · GitHub severity CRITICAL
  15. 2026-10-31 16:32 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  16. 2026-10-30 19:47 UTCGHSA enrichmentGHSA-qhgw-ghp3-xh36 · GitHub severity CRITICAL
  17. 2026-10-30 17:26 UTCEchelonGraph re-scored
  18. 2026-10-30 17:26 UTCGHSA enrichmentGHSA-qhgw-ghp3-xh36 · GitHub severity CRITICAL
  19. 2026-10-30 16:40 UTCEchelonGraph re-scored
  20. 2026-10-30 16:40 UTCGHSA enrichmentGHSA-qhgw-ghp3-xh36 · GitHub severity CRITICAL
  21. 2026-10-30 15:26 UTCGHSA enrichmentGHSA-qhgw-ghp3-xh36 · GitHub severity CRITICAL
  22. 2026-10-30 12:02 UTCENISA EUVD ID recordedEUVD-2026-113778 · Source: ENISA EUVD
  23. 2026-10-30 11:26 UTCEchelonGraph re-scored
  24. 2026-10-30 11:05 UTCEchelonGraph re-scoredFirst assessed: 9.5 CRITICAL
  25. 2026-10-30 11:04 UTCMITRE cvelistV5first tracked

Publicly available exploits

(2 references)

Public exploit code is referenced for this CVE (1 GitHub PoC), as is 1 Nuclei detection template. A detection template checks whether a system is affected; it is not necessarily exploit code. No fix is confirmed yet, so defenders should restrict or isolate affected systems accordingly until one is published.

  • Nucleihttp/cves/2026/CVE-2026-116366.yaml
    Recorded Nov 2, 2026

    ClickHouse Server - Brotli v1.2.0 Decoder DoS/OOB-Write

    Open source ↗
  • GitHub PoCgooglesky/CVE-2026-116366
    Published Oct 31, 2026

    PoC for CVE-2026-116366 — ClickHouse Server unauthenticated RCE (brotli v1.2.0 decoder out-of-bounds write): differential detector, weaponized DoS, containerized vulnerable-vs-fixed lab, root-cause analysis

    Open source ↗

Frequently asked(5)

What is CVE-2026-116366?
CVE-2026-116366 is a critical-severity vulnerability; its CVE record was published on October 30, 2026. An issue has been discovered in ClickHouse Server that, under certain conditions, could allow an unauthenticated user with network access to execute arbitrary code on the ClickHouse Server.
When was CVE-2026-116366 made public?
CVE-2026-116366 was made public on October 30, 2026: that is the date its CVE record's CNA, ClickHouse, Inc., gives for when the vulnerability was made public. The CVE record itself was published on October 30, 2026. EchelonGraph's copy of the record carries a last-modified date of October 30, 2026; the record at its source may have been updated since.
Is CVE-2026-116366 actively exploited?
CVE-2026-116366 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1.0% probability of exploitation in the next 30 days (62nd percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-116366?
CVE-2026-116366 has a CVSS base score of 9.5 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-116366?
No fix for CVE-2026-116366 is confirmed yet. Until one is published, restrict network exposure of the affected system or apply the vendor's mitigation — for example, keep it off the internet or limit it to trusted networks — and watch the vendor's advisory for the fix. The CVE record's CNA (ClickHouse, Inc.) lists ClickHouse versions 26.3 up to but not including 26.3.62.3-lts, 26.8 up to but not including 26.8.36.3-lts, 26.9 up to but not including 26.9.27.3-stable and 26.10 up to but not including 26.10.3.7-stable; ClickHouse Cloud versions 25.12 up to but not including 25.12.1.1713, 26.2 up to but not including 26.2.1.835, 26.4 up to but not including 26.4.1.2704, 26.6 up to but not including 26.6.1.2439 and 2 more ranges as affected. No release containing a fix is confirmed on record. The vendor advisories EchelonGraph has for CVE-2026-116366 are linked in the Vendor Advisories panel on this page.

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