CVE-2025-13523: Mattermost Confluence plugin version <1.7.0 fails to properly escape user-controlled display names in HTML tem

Routine

HIGH 7.7UPGRADE

CVE-2025-13523 is a high-severity flaw (CVSS 7.7) affecting confluence. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Mattermost Confluence plugin version <1.7.0 fails to properly escape user-controlled display names in HTML template rendering which allows authenticated Confluence users with malicious display names to execute arbitrary JavaScript in victim browsers via sending a specially crafted OAuth2 connection link that, when visited, renders the attacker's display name without proper sanitization. Mattermost Advisory ID: MMSA-2025-00557

Why this priority

High severity

A fixed release or distro patch exists.

Risk facts

CVSS score	7.7 (High)
Attack vector	Network (remote)
Attack complexity	High
Privileges needed	Low
User interaction	Required
EPSS exploit chance	0.2% (top 88%)
CISA exploited list	No
Weakness	CWE-79
Published	2026-02-06
Last modified	2026-06-17

Publisher (CNA): Mattermost, Inc. · Vendor: mattermost

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-02-06 16:16 UTCPublished CVE record published
2026-06-17 08:34 UTCUpdated Record last modified

mattermost confluence UPGRADE

Affected: >= 1.0.0 and < 1.7.0

Fixed in: 1.7.0

Safe to downgrade to: a release before 1.0.0

1. Check installed version

apt-cache policy confluence || rpm -q confluence || confluence --version

2. UPGRADE to 1.7.0 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade confluence

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade confluence

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 1.0.0 (Debian / Ubuntu)

apt-cache madison confluence sudo apt install confluence=<VERSION_BEFORE_1.0.0> sudo apt-mark hold confluence

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list confluence sudo dnf downgrade confluence-<VERSION_BEFORE_1.0.0> sudo dnf versionlock add confluence

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2025-13523?

confluence: upgrade to 1.7.0. Exact commands for each OS are on this page.

Is CVE-2025-13523 being exploited?

CVE-2025-13523 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2025-13523 affect?

CVE-2025-13523 affects confluence. Severity is high (CVSS 7.7). Mattermost Confluence plugin version <1.7.0 fails to properly escape user-controlled display names in HTML template rendering which allows authenticated Confluence users with malicious display names to execute arbitrary JavaScript in victim

How urgent is CVE-2025-13523?

Priority 30/100. High severity

Software pages

Atlassian Confluence vulnerabilities · Mattermost vulnerabilities

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References

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