CVE-2026-5422Public exploitNetwork attack vector

Authenticated file access via prefix-only path validation

Published Jun 2, 2026 · Updated Jun 2, 2026

Path traversal in Project Jupyter Jupyter Server 2.17.0 and earlier allows remote authenticated users to read and write sibling files. The _get_os_path() check compares an absolute path with root_dir using startswith(), while to_os_path() retains .. segments, so a sibling sharing the root prefix passes validation. Exploitation requires contents-API access and an overlapping sibling-directory name; reachable files can be read, modified, or deleted.

CVSS severity8.1
High
EPSS probability0.44%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Path traversal in Project Jupyter Jupyter Server 2.17.0 and earlier allows remote authenticated users to read and write sibling files. The _get_os_path() check compares an absolute path with root_dir using startswith(), while to_os_path() retains .. segments, so a sibling sharing the root prefix passes validation. Exploitation requires contents-API access and an overlapping sibling-directory name; reachable files can be read, modified, or deleted.

The record

CVE
CVE-2026-5422
Published
Jun 2, 2026
Updated
Jun 2, 2026
Vendor
Project Jupyter
Product
Jupyter Server
Classifications
CWE-23, T1565.001, T1005
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jun 2, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 2, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=unspecified <=latest

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Project Jupyter · Jupyter Serverversion=unspecified <=latest

Published CVSS scores

6.8huntr.devCVSS:3.0/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N
8.1NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-23Relative Path Traversal
T1565.001Stored Data Manipulation
T1005Data from Local System

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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