CVE-2026-32759Public exploitNetwork attack vector

Premature upload completion via negative upload length

Published Mar 19, 2026 · Updated Mar 19, 2026

Improper input validation in File Browser before 2.33.8 allows remote authenticated users to prematurely complete TUS uploads. The /api/tus handler accepts a negative Upload-Length as an int64, so its signed offset comparison marks an empty or partial file complete and fires after_upload hooks. Upload permission and TUS access are required; enabled exec hooks permit repeated workflow abuse and amplify malicious filenames into command execution.

CVSS severity5.3
Medium
EPSS probability1.90%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper input validation in File Browser before 2.33.8 allows remote authenticated users to prematurely complete TUS uploads. The /api/tus handler accepts a negative Upload-Length as an int64, so its signed offset comparison marks an empty or partial file complete and fires after_upload hooks. Upload permission and TUS access are required; enabled exec hooks permit repeated workflow abuse and amplify malicious filenames into command execution.

The record

CVE
CVE-2026-32759
Published
Mar 19, 2026
Updated
Mar 19, 2026
Vendor
File Browser Contributors
Product
File Browser
Classifications
CWE-190, T1190
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 19, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 19, 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=<= 2.61.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

File Browser Contributors · File Browserversion=<= 2.61.2

Published CVSS scores

8.1NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H
5.3GitHub, Inc.CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:L/SC:N/SI:L/SA:L

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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-190Integer Overflow or Wraparound
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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