CVE-2026-27611Public exploitNetwork attack vector

Protected file disclosure via tokenized download link

Published Feb 25, 2026 · Updated Feb 25, 2026

Authentication bypass in FileBrowser Quantum before 1.1.3-stable and 1.2.0-beta through 1.2.5-beta allows remote attackers to read shared files. The public /public/api/shareinfo handler serializes CommonShare with a tokenized downloadURL, exposing a bearer download link before password validation. A user must create a password-protected share, and attackers must obtain its share link; exploitation discloses that share's file contents.

CVSS severity7.1
High
EPSS probability0.31%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Authentication bypass in FileBrowser Quantum before 1.1.3-stable and 1.2.0-beta through 1.2.5-beta allows remote attackers to read shared files. The public /public/api/shareinfo handler serializes CommonShare with a tokenized downloadURL, exposing a bearer download link before password validation. A user must create a password-protected share, and attackers must obtain its share link; exploitation discloses that share's file contents.

The record

CVE
CVE-2026-27611
Published
Feb 25, 2026
Updated
Feb 25, 2026
Vendor
Graham Steffaniak
Product
FileBrowser Quantum
Classifications
CWE-602, CWE-200, CWE-288, CWE-287, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 25, 2026CVE publishedPublication date reported by the CVE source.
  2. Feb 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=< 1.1.3-stable
  2. Affected versionversion=>= 1.2.0-beta, < 1.2.6-beta

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Graham Steffaniak · FileBrowser Quantumversion=< 1.1.3-stable; version=>= 1.2.0-beta, < 1.2.6-beta

Published CVSS scores

6.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
7.1GitHub, Inc.CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/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.

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

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
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-602Client-Side Enforcement of Server-Side Security
CWE-200Exposure of Sensitive Information to an Unauthorized Actor
CWE-288Authentication Bypass Using an Alternate Path or Channel
CWE-287Improper Authentication
T1190Exploit Public-Facing Application

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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