CVE-2026-26378Public exploitNetwork attack vector

Stored script execution via inline SVG uploads

Published Jun 3, 2026 · Updated Jun 3, 2026

Stored cross-site scripting in Koha 25.11 and earlier allows remote authenticated users to run JavaScript via invoice uploads. The invoice file handler accepts an SVG labeled with an image content type and serves it inline, allowing its onload handler to execute when viewed. An account able to create an invoice and upload its attachment is required, and a second user must open the file; the script then runs in that user’s Koha origin.

CVSS severity5.4
Medium
EPSS probability0.30%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored cross-site scripting in Koha 25.11 and earlier allows remote authenticated users to run JavaScript via invoice uploads. The invoice file handler accepts an SVG labeled with an image content type and serves it inline, allowing its onload handler to execute when viewed. An account able to create an invoice and upload its attachment is required, and a second user must open the file; the script then runs in that user’s Koha origin.

The record

CVE
CVE-2026-26378
Published
Jun 3, 2026
Updated
Jun 3, 2026
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-79, T1059.007
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jun 3, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 3, 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?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

5.4CISA-ADPCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/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.

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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-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1059.007JavaScript/JScript

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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