JupyterHub through 6.0.1 contains an identifier collision vulnerability that allows authenticated users to overwrite another user's named-server OAuth client by registering a hyphenated username. Attackers holding a name like alice-prod can overwrite the client for alice's server prod, breaking OAuth login and revoking tokens by stopping their own server.
CVE-2026-108752
MEDIUMPre-NVD 4.24.2Trending — 4 sources updated this week
EchelonGraph scoreHIGH confidence
“—” beside the score: it is equal to the CVSS score beside it.
Score 4.2 from GitHub Security Advisory (severity: LOW) published 2026-10-11. A secondary CVSS source baseline 4.2; sources differ by 0.0.
Triggered by: GitHub Security Advisory CVSS
Sources: EPSS, GitHub Security Advisory, a secondary CVSS source
4.2EG
EchelonGraph verdictMonitorRemediate within your standard update timelines (the SSVC decision on this page).
- Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.2%CVSS: 4.2Exploit: None knownExposed 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 (VulnCheck) lists jupyterhub versions up to and including 6.0.1 as affected. No release containing a fix is confirmed on record.
- CVSS v3
- 4.2
- EG Score
- 4.2MEDIUMhigh confidence
- EG Risk
- 19EG Risk 19/100
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 computed (value × EchelonGraph’s weight)Severity42% × 45%The EG Score, 4.2 of 10.Exploitation0.2% × 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: No fix is confirmed yet. Restrict network exposure of the affected system or apply the vendor's mitigation within your standard update timelines, and watch the vendor's advisory for the fix. - EPSS PROB
- 0.2%
- EPSS %ILE
- 14th
- KEV
- Not listed
SSVC (CISA's decision table, applied by EchelonGraph)Track at every mission impact level.
No fix is confirmed yet. Restrict network exposure of the affected system or apply the vendor's mitigation within your standard update timelines, and watch the vendor's advisory for the fix.
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.
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 11, 2026
Last Modified
October 13, 2026
Advisory Details (3)
Auto-updated Oct 11, 2026No fix on record yet.
Web page
JupyterHub through 6.0.1 OAuth Client ID Collision via Unescaped Hyphen | Advisories | VulnCheck
https://www.vulncheck.com/advisories/jupyterhub-through-6.0.1-oauth-client-id-collision-via-unescaped-hyphenWeb page
GitHub - jupyterhub/jupyterhub: Multi-user server for Jupyter notebooks · GitHub
https://github.com/jupyterhub/jupyterhubWeb page
JupyterHub builds single-user server OAuth client ids with a single-hyphen join, so user `alice-prod` and user `alice` named server `prod` share one OAuth client and can overwrite and revoke each other - HackMD
https://hackmd.io/@haind/jupyterhub-oauth-client-id-cross-user-collisionVendor Advisories for CVE-2026-108752(1)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 13× in last 7d / 13× 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.
- 2026-10-13 17:31 UTCEG score recompute
- 2026-10-13 17:31 UTCGHSA enrichmentGHSA-h63v-vvgj-vrfh · GitHub severity LOW · GitHub CVSS 4.2
- 2026-10-13 17:08 UTCEG score recompute
- 2026-10-13 17:07 UTCGHSA enrichmentGHSA-h63v-vvgj-vrfh · GitHub severity LOW · GitHub CVSS 4.2
- 2026-10-13 16:33 UTCEPSS rescoreEPSS 0.2% · 14th percentile
- 2026-10-12 16:38 UTCEG score recompute
- 2026-10-12 16:33 UTCEPSS rescoreEPSS 0.2% · 14th percentile
- 2026-10-11 20:13 UTCEG score recompute
- 2026-10-11 18:26 UTCEG score recompute
- 2026-10-11 14:59 UTCEG score recompute
- 2026-10-11 13:19 UTCEG score recompute
- 2026-10-11 12:37 UTCEG score recomputeFirst assessed: 4.2 MEDIUM
- 2026-10-11 12:36 UTCMITRE cvelistV5first tracked
Related CVEs(same CWE)
Frequently asked(5)
What is CVE-2026-108752?
CVE-2026-108752 is a medium-severity vulnerability; its CVE record was published on October 11, 2026. JupyterHub through 6.0.1 contains an identifier collision vulnerability that allows authenticated users to overwrite another user's named-server OAuth client by registering a hyphenated username. Attackers holding a name like alice-prod can overwrite the client for alice's server prod, breaking…
When was CVE-2026-108752 made public?
CVE-2026-108752 was made public on October 10, 2026: that is the date its CVE record's CNA, VulnCheck, gives for when the vulnerability was made public. The CVE record itself was published on October 11, 2026. EchelonGraph's copy of the record carries a last-modified date of October 13, 2026; the record at its source may have been updated since.
Is CVE-2026-108752 actively exploited?
CVE-2026-108752 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.2% probability of exploitation in the next 30 days (14th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-108752?
CVE-2026-108752 has a CVSS base score of 4.2 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-108752?
No fix for CVE-2026-108752 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 (VulnCheck) lists jupyterhub versions up to and including 6.0.1 as affected. No release containing a fix is confirmed on record. The vendor advisories EchelonGraph has for CVE-2026-108752 are linked in the Vendor Advisories panel on this page.
Dependency Blast Radius
Explore the affected products and dependency analysis for CVE-2026-108752
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