CVE-2026-25133: October is a Content Management System (CMS) and web platform

Routine

MEDIUM 4.8UPGRADE

CVE-2026-25133 is a medium-severity flaw (CVSS 4.8) affecting october. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

October is a Content Management System (CMS) and web platform. Versions prior to 3.7.14 and 4.1.10 contain a stored cross-site scripting (XSS) vulnerability in the SVG sanitization logic. The regex pattern used to strip event handler attributes (such as onclick or onload) could be bypassed using a crafted payload that exploits how the pattern matches attribute boundaries, allowing malicious SVG files to be uploaded through the Media Manager with

Why this priority

No elevated risk signals yet

A fixed release or distro patch exists.

Risk facts

CVSS score	4.8 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	High
User interaction	Required
EPSS exploit chance	0.2% (top 88%)
CISA exploited list	No
Weakness	CWE-79
Published	2026-04-14
Last modified	2026-07-25

Publisher (CNA): GitHub, Inc. · Vendor: octobercms

Last updated 2026-07-25 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-04-14 21:16 UTCPublished CVE record published
2026-07-25 11:10 UTCUpdated Record last modified

octobercms october UPGRADE

Affected: <= 3.7.13 · >= 4.0.0 and <= 4.1.9

Fixed in: newer than 4.1.9

Safe to downgrade to: a release before 4.0.0

1. Check installed version

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

2. UPGRADE to newer than 4.1.9 (Debian / Ubuntu)

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

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade october

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 4.0.0 (Debian / Ubuntu)

apt-cache madison october sudo apt install october=<VERSION_BEFORE_4.0.0> sudo apt-mark hold october

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

dnf --showduplicates list october sudo dnf downgrade october-<VERSION_BEFORE_4.0.0> sudo dnf versionlock add october

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-2026-25133?

october: upgrade to newer than 4.1.9. Exact commands for each OS are on this page.

Is CVE-2026-25133 being exploited?

CVE-2026-25133 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-2026-25133 affect?

CVE-2026-25133 affects october. Severity is medium (CVSS 4.8). October is a Content Management System (CMS) and web platform. Versions prior to 3.7.14 and 4.1.10 contain a stored cross-site scripting (XSS) vulnerability in the SVG sanitization logic. The regex pattern used to strip event handler attrib

How urgent is CVE-2026-25133?

Priority 20/100. No elevated risk signals yet.

Related CVEs

CVE-2026-22692 MEDIUM 4.9 UPGRADE October is a Content Management System (CMS) and web platform
CVE-2026-24906 MEDIUM 5.4 UPGRADE October is a Content Management System (CMS) and web platform
CVE-2026-24907 MEDIUM 5.4 UPGRADE October is a Content Management System (CMS) and web platform
CVE-2026-25125 MEDIUM 4.9 UPGRADE October is a Content Management System (CMS) and web platform

References

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