dbcve.org
PycharmApplication · Jetbrains

CVE-2026-49384

MEDIUM · 6.1 CVSS v3.1 Published 2026-05-29
Fix available
A fix is available. Upgrade to 2025.3.4 or later.
See remediation →
68/100
Remediation priority · Elevated
Remotely reachable No privileges

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
In JetBrains PyCharm before 2025.3.4 stored XSS in Jupyter notebook Markdown cells was possible

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

A stored cross-site scripting (XSS) vulnerability exists in JetBrains PyCharm's Jupyter notebook functionality. Attackers can embed malicious JavaScript payloads within Markdown cells that execute when other users view the notebook. This affects versions prior to 2025.3.4.

MitigationUpgrade PyCharm to version 2025.3.4 or later. Until then, avoid opening untrusted Jupyter notebooks from unknown sources in PyCharm.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
PycharmApplication
Affected:< 2025.3.4

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
Required
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Check installed PyCharm version
    Open PyCharm and go to Help > About, or use the command: pycharm --version from terminal. Alternatively, check the installation directory for version metadata.
    Affected if The version shown is earlier than 2025.3.4 (e.g., 2025.3.3, 2025.2.x, or older)
  2. Confirm Jupyter plugin is active
    In PyCharm, navigate to Settings > Plugins > Installed and verify the 'Jupyter' plugin is enabled. Check for Jupyter notebook files (.ipynb) in recent projects.
    Affected if The Jupyter plugin is enabled and you have recently opened or created .ipynb notebook files
  3. Identify notebooks from external or untrusted sources
    Review recent notebook files opened in PyCharm. Check file metadata or source location: right-click the .ipynb file > Show in Explorer/Finder > examine the file path for indicators of external or untrusted origin.
    Affected if Notebooks from sources outside your organization, downloads from the internet, or files received via email/chat have been opened in PyCharm
  4. Inspect notebook Markdown cell content
    Open any .ipynb file in PyCharm and view the raw JSON content. Look at cells with 'cell_type': 'markdown' for HTML script tags, javascript:, or event handlers (onclick, onload, etc.) within the markdown field.
    Affected if Markdown cells contain injected HTML script tags or JavaScript event handlers that could execute when rendered

You are affected if your PyCharm version is earlier than 2025.3.4 and you have opened Jupyter notebooks containing crafted Markdown content with embedded scripts.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 2025.3.4 or later
Fixed in 2025.3.4
Interim mitigation

Upgrade PyCharm to version 2025.3.4 or later. Until then, avoid opening untrusted Jupyter notebooks from unknown sources in PyCharm.

Recommended fix High confidence

2025.3.4

  1. 1. Back up any important projects and PyCharm settings before updating
  2. 2. Open PyCharm and go to Help > Check for Updates (Windows/Linux) or PyCharm > Check for Updates (macOS)
  3. 3. In the update dialog, download and install PyCharm version 2025.3.4 or later
  4. 4. After installation, verify the version by navigating to Help > About and confirming the version number is 2025.3.4 or higher
  5. 5. Test that Jupyter notebooks with Markdown cells render correctly and the XSS vulnerability is resolved

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Pycharm Scoped from the published advisory
  • Consultation2.0 h
  • Implementation3.0 h
  • Testing2.0 h
  • Review / QA1.0 h
8.0 hours of engineering $1,420
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,272.

Scan for this in your stack

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-49384 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data