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Fedora 45 Nextcloud 34.0.4 Denial of Service and XSS Issues 2026

Linuxsecurity •LinuxSecurity Advisories • September 28, 2026

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NextCloud gives you universal access to your files through a web interface or

WebDAV. It also provides a platform to easily view & sync your contacts,

calendars and bookmarks across all your devices and enables basic editing right

on the web. NextCloud is extendable via a simple but powerful API for

applications and plugins.

* Sat Sep 19 2026 Andrew Bauer - 34.0.4-1 - 34.0.4 Release

[ 1 ] Bug #2526255 - CVE-2026-48988 nextcloud: markdown-it: Denial of Service via quadratic processing of smartquotes with typographer enabled [epel-all] [ 2 ] Bug #2526261 - CVE-2026-48988 nextcloud: markdown-it: Denial of Service via quadratic processing of smartquotes with typographer enabled [fedora-all] [ 3 ] Bug #2527333 - CVE-2026-82562 nextcloud: qs: Denial of Service via array limit bypass in query string parsing [fedora-all] [ 4 ] Bug #2527355 - CVE-2026-82562 nextcloud: qs: Denial of Service via array limit bypass in query string parsing [epel-all] [ 5 ] Bug #2527907 - CVE-2026-82417 nextcloud: qs: Denial of Service via improper validation in stringify function [epel-all]

This update can be installed with the "dnf" update program. Use su -c 'dnf upgrade --advisory FEDORA-2026-5c1bbb46c3' at the command line. For more information, refer to the dnf documentation available at

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This article is one source in a clustered incident — the cluster page carries the summary, timeline and every other outlet covering it.

Denial of Service Vulnerabilities in Nextcloud Affecting Fedora Users Multiple Denial of Service (DoS) vulnerabilities have been identified in Nextcloud version 34.0.4, affecting Fedora 43, 44, and 45 systems. The vulnerabilities include CVE-2026-48988, CVE-2026-82562, and CVE-2026-82417, all of which were published between June and August 2026. These vulnerabilities allow attackers to exploit specific functions, leading to service disruptions through improper validation and processing issues. CISA has confirmed the exploitation of these vulnerabilities, urging system administrators to apply the necessary patches. The vulnerabilities impact a wide range of users who rely on Nextcloud for file management and synchronization. Users are advised to upgrade to the latest version to mitigate risks. The updates can be installed using the 'dnf' update program. The vulnerabilities were disclosed in advisories published on September 28, 2026. 3 sources 72

Extracted Entities

Fedora 45 Nextcloud 34.0.4 Denial of Service and XSS Issues 2026

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Extracted Entities

Attack Types (1)

CVEs (3)

CWE Weaknesses (1)

Platforms (3)

Vulnerabilities (1)