Cyber Resilience

CVE-2026-23528

XSS in Anaconda Dask ≤ 2026.1.0

Published
16 January 2026
Modified
12 March 2026
Patch / advisory
CVSS Score v4 5.3
Click a component to see what it means
Raw vectorCVSS: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
EPSS Score 0.0021 11th percentile
Risk Priority 35 floored blend · peak EPSS

Summary

CVE-2026-23528 is a medium-severity Cross-site Scripting (CWE-79) vulnerability in Anaconda Dask. Its CVSS base score is 5.3 (Medium).

Operationally, exploitation aligns with the MITRE ATT&CK technique Browser Session Hijacking (T1185); ranked at the 11th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to AC-6 (Least Privilege) and SA-11 (Developer Testing and Evaluation) — see the control section below for these in your framework.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability Data

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…

more

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.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise Techniques

T1185 Browser Session Hijacking Collection
Adversaries may take advantage of security vulnerabilities and inherent functionality in browser software to change content, modify user-behaviors, and intercept information as part of various browser session hijacking techniques.
T1539 Steal Web Session Cookie Credential Access
An adversary may steal web application or service session cookies and use them to gain access to web applications or Internet services as an authenticated user without needing credentials.
T1659 Content Injection Initial Access
Adversaries may gain access and continuously communicate with victims by injecting malicious content into systems through online network traffic.
T1068 Exploitation for Privilege Escalation Privilege Escalation
Adversaries may exploit software vulnerabilities in an attempt to elevate privileges.
T1055 Process Injection Stealth
Adversaries may inject code into processes in order to evade process-based defenses as well as possibly elevate privileges.
T1189 Drive-by Compromise Initial Access
Adversaries may gain access to a system through a user visiting a website over the normal course of browsing.
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2026-34033Shared CWE-79, CWE-80
CVE-2024-49337Shared CWE-79, CWE-80
CVE-2024-45406Shared CWE-79, CWE-80
CVE-2023-47869Shared CWE-79, CWE-80
CVE-2024-37732Shared CWE-79, CWE-80
CVE-2025-25299Shared CWE-79, CWE-80
CVE-2024-6052Shared CWE-79, CWE-80
CVE-2023-30615Shared CWE-79, CWE-80
CVE-2023-20257Shared CWE-79, CWE-80
CVE-2024-42195Shared CWE-79, CWE-80

Affected Assets

anaconda
dask
≤ 2026.1.0

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

Detect
Catch it (NIST detect / respond)

Harden
Shrink the surface (DISA STIG)
  • 6 hardening rules · 6 OS baselines
Validate
Prove the fix (OWASP ASVS)
  • V10.2.3
  • V13.2.2
  • V1.1.2
  • V1.3.2

Mitigating Controls (NIST 800-53 r5) AI

Least privilege directly requires that only the minimum necessary authorizations are granted, structurally eliminating execution with unnecessary privileges.

Developer testing and evaluation can discover missing or incorrect input neutralization through targeted web-application tests.

Input validation directly enforces neutralization of untrusted data before it reaches web output generation.

Output filtering can catch or sanitize unneutralized script content before it is served to users.

Secure engineering principles include mandatory output encoding and neutralization of HTML metacharacters to stop injection at the source.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.AA-05 mostly match
prevents

PR.AA-05 directly enforces least privilege so largely eliminates CWE-250 at design time, yet the weakness can still arise from runtime escalation paths, third-party code, or misapplied role definitions outside this single control.

PR.PS-06 mostly match
prevents

Secure SDLC practices directly target introduction of XSS via coding standards/testing (mostly), yet the single broad outcome leaves many specific neutralization vectors unaddressed (partial).

PR.PS-02 partial match
prevents

Patching and EOL replacement can remediate known XSS instances in libraries or frameworks (partial) but do nothing to enforce input neutralization in application code (none).

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

prevents

Requiring explicit justification and time-limited grants discourages the routine allocation of unnecessary privileges that would otherwise allow execution with more rights than required.

prevents

Restricting privileged utilities to the fewest trusted users and requiring explicit authorization directly stops developers or operators from embedding or invoking code that runs with unnecessary elevated rights.

prevents

Mandating separate non-privileged identities for routine work and restricting privileged accounts to administrative tasks reduces the chance that everyday operations run with unnecessary elevated rights.

finds

Secure-coding testing and automated code-analysis tools are applied to detect improper neutralization of script-related content during web-page generation.

prevents

The control explicitly calls for minimizing privileged identities and disabling unnecessary accounts, thereby reducing the number of processes that run with unnecessary privileges.

prevents

The requirement to restrict privileged access and apply segregation of duties limits the number of processes or accounts that must run with elevated rights, lowering the impact of unnecessary privilege assignments.

Hardening callouts derived

Configuration rules from DISA STIG baselines that bear on weaknesses of the type cited by this CVE. Each rule is shown with the relationship its mapping actually records, against the CWE it was authored against. Derived via CVE→CWE over `controls_xwalks` (authoritative rows only; rows rated `none` are excluded).

Windows 10 (1 rule)
  • V-220712 Only accounts responsible for the administration of a system must have Administrator rights on the system. prevents CWE-250
Windows 11 (1 rule)
  • V-253269 Only accounts responsible for the administration of a system must have Administrator rights on the system. prevents CWE-250
Windows Server 2016 (1 rule)
  • V-225007 Only administrators responsible for the member server or standalone or nondomain-joined system must have Administrator rights on the system. prevents CWE-250
Windows Server 2019 (1 rule)
  • V-205746 Windows Server 2019 must only allow Administrators responsible for the member server or standalone or nondomain-joined system to have Administrator rights on the system. prevents CWE-250
Windows Server 2022 (1 rule)
  • V-254428 Windows Server 2022 must only allow administrators responsible for the member server or standalone or nondomain-joined system to have Administrator rights on the system. prevents CWE-250

References