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Full vulnerability report · 2026
CVE-2026-73416High confidence

jupyterlab: PyPI extension blocklist package-name canonicalization bypass

jupyterlab · jupyterlab

Official source article: GitHub GHSA-89VP-JRXV-24W8 ↗. Check the applicable product and release in the original source.

6.1MediumCVSS 4.0
Recommended action
Patch only the product branches with a verified fix

Medium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority. Verified remediation exists for at least one product or source, but 18 structured product or package states remain unresolved. Apply remediation only to the exact product branch confirmed by its source.

Fix availability varies by product
R
Operational reassessment

Published severity in operational context

Open reassessment dashboard →
Published severityMediumOperational priority:Medium, unchanged from published severity.unchanged

Evidence used

  • No CISA KEV confirmation is currently recorded.
  • EPSS is 0.66% for the current model date.

Compensating controls

  • Apply the linked authoritative mitigation while planning the permanent fix.
  • Restrict the affected network interface to trusted sources where business-safe.
  • Monitor vendor guidance and exploitation sources for a material change.

Verification

  1. Confirm that the asset runs jupyterlab jupyterlab and falls inside the recorded affected range.
  2. Recheck the vendor advisory before scheduling a change because no verified fixed version is currently retained.
  3. Validate exposure, authentication requirements and compensating controls in the actual environment.
  4. Reopen this reassessment when CVSS, KEV, EPSS, exploit evidence or remediation changes.
Mitigation target: As exposure requiresRemediation target: Within 365 days

This automated reassessment organises public evidence. It does not know asset exposure, business impact or control effectiveness and does not replace CVSS or a human risk decision.

Cross-source reconciliation

Remediation availability differs by product scope

Verified remediation exists for at least one product or source, but 18 structured product or package states remain unresolved. Apply remediation only to the exact product branch confirmed by its source.

Distribution package intelligence

Release-specific package status

Debian findings are scoped to the named distribution, release and source package. An absent finding does not mean a package is unaffected.

3 package states
Package result overrides the generic status

BlackTree has verified remediation for at least one product or source, but the relevant distribution still reports no fixed package for 1 affected package state shown here. Treat those rows as affected with no fix until that distribution publishes a fixed version.

Repository candidate not checked

A published vendor fix does not prove that a matching update is enabled and installable on a particular asset. Confirm the local package candidate before scheduling remediation.

Distribution releaseSource packageVendor stateFixed versionEvidence
Debian trixietrixie · sourcejupyterlabAffected, no fix publishedDebian currently tracks this release as open.Not published in this feedDebian Security Tracker ↗Source updated 6 Oct 2026
Debian forkyforky · sourcejupyterlabVendor fix publishedDebian records a fixed source-package version for this release.4.4.10+ds1+~3.1.0+~0.16.6+~cs1.4.4-4Debian Security Tracker ↗Source updated 6 Oct 2026
Debian sidsid · sourcejupyterlabVendor fix publishedDebian records a fixed source-package version for this release.4.4.10+ds1+~3.1.0+~0.16.6+~cs1.4.4-4Debian Security Tracker ↗Source updated 6 Oct 2026
Open-source package ranges4 source-attributed ranges

These OSV and GitHub advisory ranges apply only to the named package and ecosystem. A listed fixed version is not a universal product patch or proof that an update is installed.

Ecosystem and packageAffected rangeFirst fixed versionEvidence
PyPIjupyterlabECOSYSTEM: introduced 4.6.0; fixed 4.6.24.6.2OSV record ↗aggregator derived · 10 Sep 2026
PyPIjupyterlabECOSYSTEM: introduced 4.5.0; fixed 4.5.104.5.10OSV record ↗aggregator derived · 10 Sep 2026
pipjupyterlab>= 4.6.0, <= 4.6.14.6.2GitHub advisory ↗upstream repository advisory · 12 Aug 2026
pipjupyterlab>= 4.5.0, <= 4.5.94.5.10GitHub advisory ↗upstream repository advisory · 12 Aug 2026
Direct vendor intelligence

Authoritative vendor CSAF and VEX advisories

Structured product status and remediation from the issuing vendor. Product-state explanations are always visible; large lists can be searched or downloaded.

1 current
CVE-2026-73416 · CSAF 2.0 · revision 3 · finalRed Hat Product Securityjupyterlab: jupyterlab: Extension blocklist bypass via weak package-name canonicalization
17 known affected

The vendor explicitly identifies these products as affected by this CVE.

  • mta/mta-solution-server-rhel9 as a component of Migration Toolkit for Applications 8
  • rhoai/odh-feature-server-rhel9 as a component of Red Hat OpenShift AI (RHOAI)
  • rhoai/odh-th06-cpu-torch210-py312-rhel9 as a component of Red Hat OpenShift AI (RHOAI)
  • rhoai/odh-th06-cpu-torch291-py312-rhel9 as a component of Red Hat OpenShift AI (RHOAI)
  • rhoai/odh-th06-cuda130-torch210-py312-rhel9 as a component of Red Hat OpenShift AI (RHOAI)
  • rhoai/odh-th06-cuda130-torch291-py312-rhel9 as a component of Red Hat OpenShift AI (RHOAI)
  • rhoai/odh-th06-rocm64-torch291-py312-rhel9 as a component of Red Hat OpenShift AI (RHOAI)
  • rhoai/odh-workbench-jupyter-datascience-cpu-py312-rhel9 as a component of Red Hat OpenShift AI (RHOAI)
  • rhoai/odh-workbench-jupyter-minimal-cpu-py312-rhel9 as a component of Red Hat OpenShift AI (RHOAI)
  • rhoai/odh-workbench-jupyter-minimal-cuda-py312-rhel9 as a component of Red Hat OpenShift AI (RHOAI)
  • rhoai/odh-workbench-jupyter-minimal-rocm-py312-rhel9 as a component of Red Hat OpenShift AI (RHOAI)
  • rhoai/odh-workbench-jupyter-pytorch-cuda-py312-rhel9 as a component of Red Hat OpenShift AI (RHOAI)
Summary
A flaw was found in jupyterlab. The PyPI (Python Package Index) extension manager uses a custom normalization process for package names that is weaker than the official PyPI canonicalization. This allows an authenticated user to bypass blocklist restrictions by using an alternative spelling of a prohibited package name. Consequently, an attacker can install unauthorized extensions, compromise system integrity, and impact the availability of the JupyterLab environment.
Remediation
Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
Optional official sources

National CERT insights
?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.

Choose official national sources for this report. Each advisory shows its original language. Your selection is remembered on this device and included in shared links.

Official European source

ENISA European Vulnerability Database

Official EUVD identifiers, advisory evidence and known-exploited context. Missing fields are not treated as evidence of low risk.

1 current
ENISA EUVD identifier

EUVD-2026-58521

No EUVD known-exploited evidence

ENISA has published the identifier mapping but no EUVD description has been stored yet.

EUVD state
Present in the current official mapping
Known exploitation
Not present in the current ENISA EUVD known-exploited dataset. This is not proof of no exploitation.
ENISA score
Not supplied in the stored EUVD record
Advisory evidence
No linked advisory details stored yet
Recommended actionPatch only the product branches with a verified fix

Medium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority. Verified remediation exists for at least one product or source, but 18 structured product or package states remain unresolved. Apply remediation only to the exact product branch confirmed by its source.

Fix availability varies by product
01

What, why and how

jupyterlab is an extensible environment for interactive and reproducible computing, based on the Jupyter Notebook Architecture. From 4.5.0 until 4.5.10 and 4.6.2, in jupyterlab/extensions/manager.py and jupyterlab/extensions/pypi.py, JupyterLab's PyPI extension manager enforces blocked_extensions_uris by comparing requested install names to blocklist entries with custom normalization that is weaker than PyPI package-name canonicalization. An authenticated user can request a PyPI-equivalent spelling such as JupyterLab.Git for a blocklisted package such as jupyterlab-git, and JupyterLab accepts the install request even though pip resolves the variant to the same package. Security impact requires an allowlist or blocklist intended to restrict package installation, the PyPI Extension Manager, and kernels and terminals that are disabled or delegated to remote hosts. The bypass lets an authenticated user install a prohibited extension, defeat integrity restrictions, and affect availability without gaining new read access. This issue is fixed in versions 4.5.10 and 4.6.2.

What

jupyterlab is an extensible environment for interactive and reproducible computing, based on the Jupyter Notebook Architecture. From 4.5.0 until 4.5.10 and 4.6.2, in jupyterlab/extensions/manager.py and jupyterlab/extensions/pypi.py, JupyterLab's PyPI extension manager enforces blocked_extensions_uris by comparing requested install names to blocklist entries with custom normalization that is weaker than PyPI package-name canonicalization. An authenticated user can request a PyPI-equivalent spelling such as JupyterLab.Git for a blocklisted package such as jupyterlab-git, and JupyterLab accepts the install request even though pip resolves the variant to the same package. Security impact requires an allowlist or blocklist intended to restrict package installation, the PyPI Extension Manager, and kernels and terminals that are disabled or delegated to remote hosts. The bypass lets an authenticated user install a prohibited extension, defeat integrity restrictions, and affect availability without gaining new read access. This issue is fixed in versions 4.5.10 and 4.6.2.

Why

The product does not properly account for differences in case sensitivity when accessing or determining the properties of a resource, leading to inconsistent results.

How

An attacker operating through a network path may attempt exploitation with low privileges. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

What

jupyterlab is an extensible environment for interactive and reproducible computing, based on the Jupyter Notebook Architecture. From 4.5.0 until 4.5.10 and 4.6.2, in jupyterlab/extensions/manager.py and jupyterlab/extensions/pypi.py, JupyterLab's PyPI extension manager enforces blocked_extensions_uris by comparing requested install names to blocklist entries with custom normalization that is weaker than PyPI package-name canonicalization. An authenticated user can request a PyPI-equivalent spelling such as JupyterLab.Git for a blocklisted package such as jupyterlab-git, and JupyterLab accepts the install request even though pip resolves the variant to the same package. Security impact requires an allowlist or blocklist intended to restrict package installation, the PyPI Extension Manager, and kernels and terminals that are disabled or delegated to remote hosts. The bypass lets an authenticated user install a prohibited extension, defeat integrity restrictions, and affect availability without gaining new read access. This issue is fixed in versions 4.5.10 and 4.6.2.

Why

The product does not properly account for differences in case sensitivity when accessing or determining the properties of a resource, leading to inconsistent results.

How

An attacker operating through a network path may attempt exploitation with low privileges. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

02

Exploit reality and attack path

CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.

Observed exploitation
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
No confirmed evidence

No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.

Public PoC / exploit material
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
None recorded

No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.

Likely attack path
a network path → Improper Handling of Case Sensitivity → cause the confidentiality, integrity or availability impact described by the vendor
Attack surface
Network
Privileges required
Low: a basic authenticated account is required
User interaction
None
Attack complexity
Low: no specialised conditions are recorded
Security boundary
Not a CVSS 4.0 base metric
Weakness
?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-178 ↗

CWE-178: Improper Handling of Case Sensitivity. The product does not properly account for differences in case sensitivity when accessing or determining the properties of a resource, leading to inconsistent results.

CVSS vector
?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:L/VI:H/VA:L/SC:N/SI:N/SA:N

Common Vulnerability Scoring System 4.0: the compact vector below is decoded into plain language.

AVNetworkAttack vector: The vulnerable component can be reached over a network.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.ATPresentAttack requirements: A particular deployment or execution condition must be present.PRLowPrivileges required: The attacker needs basic user-level privileges.UINoneUser interaction: No action by another user is required.VCLowVulnerable-system confidentiality: A successful attack can cause a limited loss.VIHighVulnerable-system integrity: A successful attack can cause a major loss.VALowVulnerable-system availability: A successful attack can cause a limited loss.SCNoneSubsequent-system confidentiality: No direct loss is represented by this metric.SINoneSubsequent-system integrity: No direct loss is represented by this metric.SANoneSubsequent-system availability: No direct loss is represented by this metric.
Post-exploitation / living off the land
No specific living-off-the-land technique is confirmed in the structured sources. Monitor normal administration tools for activity inconsistent with the affected service's baseline.
NetworkCWE-178
A

Official authority intelligence

Only matched European and national findings are included. Language selectors and unavailable sources are omitted.

Cyber Security Agency of Singapore · English · CSA-SB-20260819Security Bulletin 19 Aug 2026

The Cyber Security Agency of Singapore included this CVE in its official Security Bulletin 19 Aug 2026, published on 19 August 2026. Open the linked bulletin for the product, severity and reference information published in that issue.

Official advisory ↗
03

Patch and workaround

Operational remediation based on structured source evidence.

Status
?Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.
Fix availability varies by product
Affected
Fixed
No fixed version is explicitly recorded in the structured CVE data.
Action
Use the product-specific evidence above. Patch only products with a verified fixed release, and keep every affected or under-investigation state without a matching fix in the remediation queue.
Workaround
Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
04

Evidence and provenance

Published 13 Aug 2026 · Last source change 17 Aug 2026, 17:17 UTC · CWE-178 · Improper Handling of Case Sensitivity

CVE recordCVE.org · 5.2
CVSS sourceCNA
EPSS source
?The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.
FIRST · tracked since 2026-08-14
European sourceENISA EUVD · EUVD-2026-58521
Product sourceVendor CSAF · Red Hat Product Security
Remediation sourceVendor CSAF · Red Hat Product Security
CWE sourceCNA
NVD statusNVD awaiting enrichment

Core structured fields are present and their contributing authorities are shown above.

Material change intelligence

What changed after publication

View recent updates ↗
  1. Vendor guidanceAuthoritative vendor guidance changed from remediation: access.redhat.com/CVE-2026-73416 to remediation: access.redhat.com/CVE-2026-73416.
    Before
    remediation: access.redhat.com/CVE-2026-73416
    After
    remediation: access.redhat.com/CVE-2026-73416
    Red Hat Product Security ↗
  2. Remediation statusRemediation status changed from Awaiting fix to Mitigation available.
    Before
    Awaiting fix
    After
    Mitigation available
    Red Hat Product Security ↗
  3. Vendor guidanceAuthoritative vendor guidance changed from remediation: access.redhat.com/CVE-2026-73416 to remediation: access.redhat.com/CVE-2026-73416.
    Before
    remediation: access.redhat.com/CVE-2026-73416
    After
    remediation: access.redhat.com/CVE-2026-73416
    Red Hat Product Security ↗
  4. Affected versionsThe structured affected or fixed version information changed.
    Before
    After
    mta/mta-solution-server-rhel9 as a component of Migration Toolkit for Applications 8; rhoai/odh-feature-server-rhel9 as a component of Red Hat OpenShift AI (RHOAI); rhoai/odh-th06-cpu-torch210-py312-rhel9 as a component of Red Hat OpenShift AI (RHOAI); rhoai/odh-th06-cpu-torch291-py312-rhel9 as a component of Red Hat OpenShift AI (RHOAI); rhoai/odh-th06-cuda130-torch210-py312-rhel9 as a component of Red Hat OpenShift AI (RHOAI); rhoai/odh-th06-cuda130-torch291-py312-rhel9 as a component of Red Hat OpenShift AI (RHOAI); rhoai/odh-th06-rocm64-torch291-py312-rhel9 as a component of Red Hat OpenShift AI (RHOAI); rhoai/odh-workbench-jupyter-datascience-cpu-py312-rhel9 as a component of Red Hat OpenShift AI (RHOAI); rhoai/odh-workbench-jupyter-minimal-cpu-py312-rhel9 as a component of Red Hat OpenShift AI (RHOAI); rhoai/odh-workbench-jupyter-minimal-cuda-py312-rhel9 as a component of Red Hat OpenShift AI (RHOAI); rhoai/odh-workbench-jupyter-minimal-rocm-py312-rhel9 as a component of Red Hat OpenShift AI (RHOAI); rhoai/odh-workbench-jupyter-pytorch-cuda-py312-rhel9 as a component of Red Hat OpenShift AI (RHOAI); rhoai/odh-workbench-jupyter-pytorch-llmcompressor-cuda-py312-rhel9 as a component of Red Hat OpenShift AI (RHOAI); rhoai/odh-workbench-jupyter-pytorch-rocm-py312-rhel9 as a component of Red Hat OpenShift AI (RHOAI); rhoai/odh-workbench-jupyter-tensorflow-cuda-py312-rhel9 as a component of Red Hat OpenShift AI (RHOAI); rhoai/odh-workbench-jupyter-tensorflow-rocm-py312-rhel9 as a component of Red Hat OpenShift AI (RHOAI); rhoai/odh-workbench-jupyter-trustyai-cpu-py312-rhel9 as a component of Red Hat OpenShift AI (RHOAI)
    Red Hat Product Security ↗
  5. Affected versionsThe structured affected or fixed version information changed.
    Before
    >= 4.5.0, < 4.5.10; >= 4.6.0, < 4.6.2 · Fixed: No fixed version is explicitly recorded in the structured CVE data.
    After
    jupyterlab: >= 4.5.0, < 4.5.10, >= 4.6.0, < 4.6.2 · Fixed: No fixed version is explicitly recorded in the structured CVE data.
    CNA ↗
Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
ENISA EUVD · EUVD-2026-58521↗Vendor CSAF · Red Hat Product Security↗CVE authority or vendor reference · GitHub GHSA-89VP-JRXV-24W8↗Official CVE record (CNA and ADP data)↗NVD record↗
Technical terms and abbreviations used in this report
CVE
Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS
Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS
Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE
Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA
CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP
Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD
National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT
A computer security incident response team that publishes warnings or coordinates incident response.
PoC
Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF
Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL
Living off the land: abuse of legitimate tools or system functions during an attack.
Free version - for non-commercial use only.CVE-2026-73416 · cve.blacktree.nl