Is CVE-2026-26378 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-26378 being exploited in the wild.

How severe is CVE-2026-26378?

Informational severity, with a CVSS score of 6.1, published 3 June 2026.

Is there a fix for CVE-2026-26378?

No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

How is CVE-2026-26378 attacked?

It is attacked over the network, in a network appliance.

Am I affected by CVE-2026-26378?

Check whether you run Koha Community Koha at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-26378: Koha XSS via SVG file upload in Invoice features

CVE-2026-26378 · Severity: info · CVSS 6.1 · Published 2026-06-03

Koha, an open-source integrated library system, is vulnerable to a security flaw in its invoice management feature. An attacker can upload a specially crafted file that, when viewed by a staff member or administrator, executes malicious code in their web browser. This could allow an attacker to steal session information, perform actions on behalf of the user, or access sensitive library data.

Technologies: Koha Community Koha. Vendors: Koha Community.

Quick answers

Is CVE-2026-26378 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-26378 being exploited in the wild.
How severe is CVE-2026-26378?: Informational severity, with a CVSS score of 6.1, published 3 June 2026.
Which products and versions are affected?: Koha Community Koha <= 25.11.
Is there a fix for CVE-2026-26378?: No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
How is CVE-2026-26378 attacked?: It is attacked over the network, in a network appliance.
Am I affected by CVE-2026-26378?: Check whether you run Koha Community Koha at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

A stored Cross-Site Scripting (XSS) vulnerability exists in Koha versions up to and including 25.11 within the 'Invoice' file upload functionality (specifically cgi-bin/koha/acqui/invoice-files.pl). The application fails to properly sanitize uploaded files and allows inline rendering of SVG files with image Content-Types. An attacker can upload an SVG file containing a malicious JavaScript payload (e.g., using the 'onload' attribute). When an authenticated user views the uploaded file, the script executes within the context of their browser session, potentially leading to session hijacking or unauthorized administrative actions.

Affected products

Koha Community Koha <= 25.11

Timeline

2025-12-31: disclosed: Initial researcher write-up published
2026-06-03: advisory: CVE published to NVD dataset

References

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