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Not in CISA KEV
HIGH severity

CVE-2023-5256 — core

HIGHFix: drupal/core@1cd2741

CVE-2023-5256 is a high-severity (CVSS 7.5) Information Exposure vulnerability in drupal/core. A fix is available for drupal/core — see the affected versions and patch details below.

Drupal core - Critical - Cache poisoning - SA-CORE-2023-006

Also known asBIT-drupal-2023-5256DRUPAL-CORE-2023-006GHSA-rjqg-3h9m-fx5x
Published
Updated
Affected
3 pkgs
Patched
3 / 3
Exploits
None indexed
Exploitation data as of Nov 10, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

  • A successful exploit gives an attacker total control of the affected component, not partial access.
  • CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2023-5256.

EPSS Exploitation Probability

via FIRST.org ↗
0.9%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs59th percentile — riskier than 59% of all scored CVEsHighest risk
0.19%0.73%1.26%1.80%1.3%0.9%May 26Sep 26Nov 26

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

3 pkgs affected
🐘drupal/core🐘drupal/core🐘drupal/core

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.

Description

In certain scenarios, Drupal's JSON:API module will output error backtraces. With some configurations, this may cause sensitive information to be cached and made available to anonymous users, leading to privilege escalation.

This vulnerability only affects sites with the JSON:API module enabled, and can be mitigated by uninstalling JSON:API.

The core REST and contributed GraphQL modules are not affected.

Affected Packages

3 total 3 fixed
EcosystemPackageVulnerable rangeFix
🐘Packagistdrupal/core≥ 8.7.0&&< 9.5.119.5.11composer require drupal/core:^9.5.11
🐘Packagistdrupal/core≥ 10.0.0&&< 10.0.1110.0.11composer require drupal/core:^10.0.11
🐘Packagistdrupal/core≥ 10.1.0&&< 10.1.410.1.4composer require drupal/core:^10.1.4

Affected Products

1 product · 3 configurations
Application
drupaldrupal
≥ 10.1.0 && < 10.1.4
range

Detection & mitigation playbook

Open-source dependency

  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for drupal/core, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update drupal/core to 9.5.11 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-5256 is resolved across your whole dependency graph.

  3. Workarounds

    Close the privilege gap rather than the entry point: audit which accounts, roles and service identities can reach the affected operation, drop the component to the least privilege it actually needs, and review file and directory permissions created by earlier installs — a default left in place is what makes this reachable.

Frequently Asked Questions

In certain scenarios, Drupal's JSON:API module will output error backtraces. With some configurations, this may cause sensitive information to be cached and made available to anonymous users, leading to privilege escalation. This vulnerability only affects sites with the JSON:API module enabled, and can be mitigated by uninstalling JSON:API. The core REST and contributed GraphQL modules are not affected.
O3 Security · Impact-Aware SCA

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CVE-2023-5256: core PrivEsc — Fixed in 9.5.11