CVE-2026-23528
Dask distributed Vulnerable to Remote Code Execution via Jupyter Proxy and Dashboard
Dask distributed is a distributed task scheduler for Dask. Prior to 2026.1.0, when Jupyter Lab, jupyter-server-proxy, and Dask distributed are all run together, it is possible to craft a URL which will result in code being executed by Jupyter due to a cross-side-scripting (XSS) bug in the Dask dashboard. It is possible for attackers to craft a phishing URL that assumes Jupyter Lab and Dask may be running on localhost and using default ports. If a user clicks on the malicious link it will open an error page in the Dask Dashboard via the Jupyter Lab proxy which will cause code to be executed by the default Jupyter Python kernel. This vulnerability is fixed in 2026.1.0.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- Passive
What an attacker can affect
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used
Dask distributed Vulnerable to Remote Code Execution via Jupyter Proxy and Dashboard
Dask distributed is a distributed task scheduler for Dask. Prior to 2026.1.0, when Jupyter Lab, jupyter-server-proxy, and Dask distributed are all run together, it is possible to craft a URL which will result in code being executed by Jupyter due to a cross-side-scripting (XSS) bug in the Dask dashboard. It is possible for attackers to craft a phishing URL that assumes Jupyter Lab and Dask may be running on localhost and using default ports. If a user clicks on the malicious link it will open an error page in the Dask Dashboard via the Jupyter Lab proxy which will cause code to be executed by the default Jupyter Python kernel. This vulnerability is fixed in 2026.1.0.
- Record
CVE-2026-23528- CVSS 4.0
- 5.3 Medium
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N - Weakness
- CWE-80, CWE-250, CWE-79
- Updated
- 2026-11-02
EUVDEUVD-2026-2922
Dask distributed is a distributed task scheduler for Dask. Prior to 2026.1.0, when Jupyter Lab, jupyter-server-proxy, and Dask distributed are all run together, it is possible to craft a URL which will result in code being executed by Jupyter due to a cross-side-scripting (XSS) bug in the Dask dashboard. It is possible for attackers to craft a phishing URL that assumes Jupyter Lab and Dask may be running on localhost and using default ports. If a user clicks on the malicious link it will open an error page in the Dask Dashboard via the Jupyter Lab proxy which will cause code to be executed by the default Jupyter Python kernel. This vulnerability is fixed in 2026.1.0.
- Record
EUVD-2026-2922- CVSS 4.0
- 5.3 Medium
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-c336-7962-wfj2
Dask Distributed is Vulnerable to Remote Code Execution via Jupyter Proxy and Dashboard
Impact
When Jupyter Lab, jupyter-server-proxy and Dask distributed are all run together it is possible to craft a URL which will result in code being executed by Jupyter due to a cross-side-scripting (XSS) bug in the Dask dashboard.
It is possible for attackers to craft a phishing URL that assumes Jupyter Lab and Dask may be running on localhost and using default ports. If a user clicks on the malicious link it will open an error page in the Dask Dashboard via the Jupyter Lab proxy which will cause code to be executed by the default Jupyter Python kernel.
In order for a user to be impacted they must be running Jupyter Lab locally on the default port (with the jupyter-server-proxy) and a Dask distributed cluster on the default port. Then they would need to click the link which would execute the malicious code.
Patches
This has been fixed in the 2026.1.0 release. All users should upgrade to this version.
Mitigations
There are no known workarounds for this bug. The only complete solution is to upgrade to a newer release of Dask. However, there are a few things you could do to reduce your risk.
It is possible to avoid code execution via Jupyter by uninstalling the jupyter-server-proxy and accessing the Dask dashboard directly at it's URL. However, it is still possible for an attacker to craft a URL that executes JavaScript in the user's browser in the Dask dashboard. Which is still a moderate vulnerability. Therefore we recommend all users upgrade to the latest Dask release.
Another potential mitigation is to ensure both Jupyter and the Dask dashboard are running on non-standard ports. While this doesn't resolve the problem it reduces the chance of this being exploited. If an attacker knew which ports you were using they could still craft a malicious URL, but it would require a more targeted attack.
- Record
GHSA-c336-7962-wfj2- CVSS 4.0
- 5.3 Medium
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N - Weakness
- CWE-79, CWE-250
- Updated
- 2026-11-02
NVD
Dask distributed is a distributed task scheduler for Dask. Prior to 2026.1.0, when Jupyter Lab, jupyter-server-proxy, and Dask distributed are all run together, it is possible to craft a URL which will result in code being executed by Jupyter due to a cross-side-scripting (XSS) bug in the Dask dashboard. It is possible for attackers to craft a phishing URL that assumes Jupyter Lab and Dask may be running on localhost and using default ports. If a user clicks on the malicious link it will open an error page in the Dask Dashboard via the Jupyter Lab proxy which will cause code to be executed by the default Jupyter Python kernel. This vulnerability is fixed in 2026.1.0.
- Record
CVE-2026-23528- CVSS 4.0
- 5.3 Medium
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - CVSS 3.1
- 6.1 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N - Weakness
- CWE-79, CWE-80, CWE-250
- Updated
- 2026-11-02
OSV
Dask distributed Vulnerable to Remote Code Execution via Jupyter Proxy and Dashboard
Dask distributed is a distributed task scheduler for Dask. Prior to 2026.1.0, when Jupyter Lab, jupyter-server-proxy, and Dask distributed are all run together, it is possible to craft a URL which will result in code being executed by Jupyter due to a cross-side-scripting (XSS) bug in the Dask dashboard. It is possible for attackers to craft a phishing URL that assumes Jupyter Lab and Dask may be running on localhost and using default ports. If a user clicks on the malicious link it will open an error page in the Dask Dashboard via the Jupyter Lab proxy which will cause code to be executed by the default Jupyter Python kernel. This vulnerability is fixed in 2026.1.0.
- Record
CVE-2026-23528- CVSS 4.0
- 5.3 Medium
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N - Weakness
- CWE-250, CWE-79, CWE-80
- Updated
- 2026-11-02
OSVDEBIAN-CVE-2026-23528
Dask distributed is a distributed task scheduler for Dask. Prior to 2026.1.0, when Jupyter Lab, jupyter-server-proxy, and Dask distributed are all run together, it is possible to craft a URL which will result in code being executed by Jupyter due to a cross-side-scripting (XSS) bug in the Dask dashboard. It is possible for attackers to craft a phishing URL that assumes Jupyter Lab and Dask may be running on localhost and using default ports. If a user clicks on the malicious link it will open an error page in the Dask Dashboard via the Jupyter Lab proxy which will cause code to be executed by the default Jupyter Python kernel. This vulnerability is fixed in 2026.1.0.
- Record
DEBIAN-CVE-2026-23528- CVSS 3.1
- 6.1 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N - Updated
- 2026-11-02
OSVGHSA-c336-7962-wfj2
Dask Distributed is Vulnerable to Remote Code Execution via Jupyter Proxy and Dashboard
Impact
When Jupyter Lab, jupyter-server-proxy and Dask distributed are all run together it is possible to craft a URL which will result in code being executed by Jupyter due to a cross-side-scripting (XSS) bug in the Dask dashboard.
It is possible for attackers to craft a phishing URL that assumes Jupyter Lab and Dask may be running on localhost and using default ports. If a user clicks on the malicious link it will open an error page in the Dask Dashboard via the Jupyter Lab proxy which will cause code to be executed by the default Jupyter Python kernel.
In order for a user to be impacted they must be running Jupyter Lab locally on the default port (with the jupyter-server-proxy) and a Dask distributed cluster on the default port. Then they would need to click the link which would execute the malicious code.
Patches
This has been fixed in the 2026.1.0 release. All users should upgrade to this version.
Mitigations
There are no known workarounds for this bug. The only complete solution is to upgrade to a newer release of Dask. However, there are a few things you could do to reduce your risk.
It is possible to avoid code execution via Jupyter by uninstalling the jupyter-server-proxy and accessing the Dask dashboard directly at it's URL. However, it is still possible for an attacker to craft a URL that executes JavaScript in the user's browser in the Dask dashboard. Which is still a moderate vulnerability. Therefore we recommend all users upgrade to the latest Dask release.
Another potential mitigation is to ensure both Jupyter and the Dask dashboard are running on non-standard ports. While this doesn't resolve the problem it reduces the chance of this being exploited. If an attacker knew which ports you were using they could still craft a malicious URL, but it would require a more targeted attack.
- Record
GHSA-c336-7962-wfj2- CVSS 4.0
- 5.3 Medium
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N - Weakness
- CWE-250, CWE-79
- Updated
- 2026-11-02
OSVPYSEC-2026-169
Dask distributed is a distributed task scheduler for Dask. Prior to 2026.1.0, when Jupyter Lab, jupyter-server-proxy, and Dask distributed are all run together, it is possible to craft a URL which will result in code being executed by Jupyter due to a cross-side-scripting (XSS) bug in the Dask dashboard. It is possible for attackers to craft a phishing URL that assumes Jupyter Lab and Dask may be running on localhost and using default ports. If a user clicks on the malicious link it will open an error page in the Dask Dashboard via the Jupyter Lab proxy which will cause code to be executed by the default Jupyter Python kernel. This vulnerability is fixed in 2026.1.0.
- Record
PYSEC-2026-169- CVSS 3.1
- 6.1 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N - Updated
- 2026-11-02
OSVUBUNTU-CVE-2026-23528
Dask distributed is a distributed task scheduler for Dask. Prior to 2026.1.0, when Jupyter Lab, jupyter-server-proxy, and Dask distributed are all run together, it is possible to craft a URL which will result in code being executed by Jupyter due to a cross-side-scripting (XSS) bug in the Dask dashboard. It is possible for attackers to craft a phishing URL that assumes Jupyter Lab and Dask may be running on localhost and using default ports. If a user clicks on the malicious link it will open an error page in the Dask Dashboard via the Jupyter Lab proxy which will cause code to be executed by the default Jupyter Python kernel. This vulnerability is fixed in 2026.1.0.
- Record
UBUNTU-CVE-2026-23528- CVSS 4.0
- 5.3 Medium
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N - CVSS 3.1
- 6.1 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N - Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
distributedPyPI |
before 2026.1.0 | 2026.1.0 |
dask.distributedDebian:12 |
All versions, plus listed versions 2022.12.1+ds.1-32023.12.1+ds-12023.12.1+ds-22023.12.1+ds-32023.12.1+ds-4 Show 12 moreShow less2023.8.0+ds.1-12024.12.1+ds-12024.12.1+ds-22024.12.1+ds-32024.5.2+ds.1-12024.5.2+ds.1-22024.5.2+ds.1-32024.5.2+ds.1-42024.5.2+ds.1-52024.5.2+ds.1-62024.5.2+ds.1-72024.5.2+ds.1-8 |
None known |
dask.distributedDebian:13 |
All versions, plus listed versions 2024.12.1+ds-12024.12.1+ds-22024.12.1+ds-3 |
None known |
dask.distributedDebian:14 |
before 2024.12.1+ds-3, plus listed versions 2024.12.1+ds-12024.12.1+ds-2 |
2024.12.1+ds-3 |
distributedPyPI |
before 2026.1.0, plus listed versions 1.0.01.0.11.0.21.1.01.10.0 Show 45 moreShow less1.10.11.10.21.11.01.11.11.11.21.11.31.12.01.12.11.12.21.13.01.13.11.13.21.13.31.14.01.14.11.14.31.15.01.15.0rc11.15.11.15.21.16.01.16.11.16.21.16.31.17.01.17.11.18.01.18.11.18.21.18.31.19.01.19.11.19.21.19.31.2.01.2.11.2.21.2.31.20.01.20.11.20.21.21.01.21.11.21.21.21.3 |
2026.1.0 |
distributedPyPI |
before 2026.1.0, plus listed versions 1.0.01.0.11.0.21.1.01.10.0 Show 45 moreShow less1.10.11.10.21.11.01.11.11.11.21.11.31.12.01.12.11.12.21.13.01.13.11.13.21.13.31.14.01.14.11.14.31.15.01.15.0rc11.15.11.15.21.16.01.16.11.16.21.16.31.17.01.17.11.18.01.18.11.18.21.18.31.19.01.19.11.19.21.19.31.2.01.2.11.2.21.2.31.20.01.20.11.20.21.21.01.21.11.21.21.21.3 |
2026.1.0 |
dask.distributedUbuntu:18.04:LTS |
All versions, plus listed versions 1.18.0+ds.1-11.20.2+ds.1-11.20.2+ds.1-2 |
None known |
dask.distributedUbuntu:20.04:LTS |
All versions, plus listed versions 1.25.0+ds.1-1 |
None known |
dask.distributedUbuntu:22.04:LTS |
All versions, plus listed versions 2021.01.0+ds.1-2.12021.09.1+ds.1-32022.01.0+ds.1-1 |
None known |
dask.distributedUbuntu:24.04:LTS |
All versions, plus listed versions 2023.8.0+ds.1-12023.12.1+ds-32023.12.1+ds-4 |
None known |
dask.distributedUbuntu:25.10 |
All versions, plus listed versions 2024.12.1+ds-1 |
None known |
dask.distributedUbuntu:26.10 |
All versions, plus listed versions 2024.12.1+ds-12024.12.1+ds-22024.12.1+ds-3 |
None known |
dask.distributedUbuntu:26.04:LTS |
All versions, plus listed versions 2024.12.1+ds-1 |
None known |
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-23528 is a medium vulnerability (CVSS 5.3) in Anaconda Dask, published January 16, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.24%, the 14th percentile. Fixed in distributed 2026.1.0.
References
github.com/dask/distributed/security/advisories/GHSA-c336-7962-wfj2
nvd.nist.gov/vuln/detail/CVE-2026-23528
Left out here: 419 versions. The JSON record has them.