CVE-2026-55803: Improperly Controlled Modification of Dynamically-Determined Object Attributes vulnerability in Drupal Drupal

Routine

MEDIUM 5.9UPGRADE

CVE-2026-55803 is a medium-severity flaw (CVSS 5.9) affecting drupal. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Improperly Controlled Modification of Dynamically-Determined Object Attributes vulnerability in Drupal Drupal core allows Object Injection. This issue affects Drupal core versions: from 0.0.0 to 10.5.12, from 10.6.0 to 10.6.11, from 11.2.0 to 11.2.14, from 11.3.0 to 11.3.12, from 0.0.0 to 11.0.*, from 0.0.0 to 11.1.*.

Why this priority

No elevated risk signals yet

A fixed release or distro patch exists.

Risk facts

CVSS score	5.9 (Medium)
Attack vector	Network (remote)
Attack complexity	High
Privileges needed	High
User interaction	None
EPSS exploit chance	0.4% (top 71%)
CISA exploited list	No
Weakness	CWE-915
Published	2026-07-10
Last modified	2026-10-25

Publisher (CNA): Drupal.org · Vendor: drupal

Last updated 2026-10-25 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-07-10 22:16 UTCPublished CVE record published
2026-10-25 15:10 UTCUpdated Record last modified

drupal drupal UPGRADE

Affected: < 10.5.12 · >= 10.6.0 and < 10.6.11 · >= 11.0.0 and < 11.2.14 · >= 11.3.0 and < 11.3.12

Fixed in: 10.5.12, 10.6.11, 11.2.14, 11.3.12

Safe to downgrade to: a release before 10.6.0

1. Check installed version

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

2. UPGRADE to 10.5.12 (Debian / Ubuntu)

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

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade drupal

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 10.6.0 (Debian / Ubuntu)

apt-cache madison drupal sudo apt install drupal=<VERSION_BEFORE_10.6.0> sudo apt-mark hold drupal

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

dnf --showduplicates list drupal sudo dnf downgrade drupal-<VERSION_BEFORE_10.6.0> sudo dnf versionlock add drupal

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.

Advisories and coverage

Official advisories

Drupal Security: Drupal core - Critical - PHP object injection - SA-CORE-2026-005 2026-06-17

Research and news

Mandiant / Google Cloud Threat Intel: Staying Ahead of Adversarial AI Through Agentic Source Code Review 2026-08-18

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-2026-55803?

drupal: upgrade to 10.5.12, 10.6.11, 11.2.14, 11.3.12. Exact commands for each OS are on this page.

Is CVE-2026-55803 being exploited?

CVE-2026-55803 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-2026-55803 affect?

CVE-2026-55803 affects drupal. Severity is medium (CVSS 5.9). Improperly Controlled Modification of Dynamically-Determined Object Attributes vulnerability in Drupal Drupal core allows Object Injection. This issue affects Drupal core versions: from 0.0.0 to 10.5.12, from 10.6.0 to 10.6.11, from 11.2.0

How urgent is CVE-2026-55803?

Priority 28/100. No elevated risk signals yet.

Software pages

Drupal vulnerabilities

Related CVEs

CVE-2026-55806 MEDIUM 5.9 UPGRADE URL Redirection to Untrusted Site ('Open Redirect') vulnerability in Drupal Drupal core allows Content Spoofin
CVE-2026-55804 MEDIUM 5.9 UPGRADE Improperly Controlled Modification of Dynamically-Determined Object Attributes vulnerability in Drupal Drupal
CVE-2026-55808 MEDIUM 5.4 UPGRADE Improper Neutralization of Input During Web Page Generation ("Cross-site Scripting") vulnerability in Drupal D
CVE-2026-55807 LOW 3.1 UPGRADE Server-Side Request Forgery (SSRF) vulnerability in Drupal Drupal core allows Server Side Request Forgery

References

← Back to latest CVEs