CVE-2026-54573Public exploitNetwork attack vector

Authenticated scope escalation via URL fragment parsing

Published Jun 25, 2026 · Updated Jun 25, 2026

Incorrect authorization in Outline before 1.8.0 allows remote authenticated users to create documents with a read-only API key. AuthenticationHelper.canAccess splits ctx.originalUrl and trusts its last slash-delimited segment without removing a URL fragment, while Koa routes on fragment-free ctx.path. A key or OAuth token with a permitted read scope can append that route in a fragment to a restricted API endpoint and perform the restricted write.

CVSS severity5.3
Medium
EPSS probability0.50%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Incorrect authorization in Outline before 1.8.0 allows remote authenticated users to create documents with a read-only API key. AuthenticationHelper.canAccess splits ctx.originalUrl and trusts its last slash-delimited segment without removing a URL fragment, while Koa routes on fragment-free ctx.path. A key or OAuth token with a permitted read scope can append that route in a fragment to a restricted API endpoint and perform the restricted write.

The record

CVE
CVE-2026-54573
Published
Jun 25, 2026
Updated
Jun 25, 2026
Vendor
Outline
Product
Outline
Classifications
CWE-863
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jun 25, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 25, 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=< 1.8.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Outline · Outlineversion=< 1.8.0

Published CVSS scores

5.3GitHub, Inc.CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA: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.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-863Incorrect Authorization

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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