CVE-2020-13665Network attack vector

Authenticated field modification via JSON API validation bypass

Published May 5, 2021 · Updated Aug 4, 2024

Access bypass in Drupal Core 8.8.0 through 8.8.7, 8.9.0, and 9.0.0 allows remote authenticated users to alter protected fields. The JSON:API module accepts PATCH requests for certain fields without enforcing their validation constraints. Exploitation requires JSON:API read/write mode, with jsonapi.settings read_only set to FALSE; the default read-only mode blocks the write.

CVSS severity9.8
Critical
EPSS probability1.27%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Access bypass in Drupal Core 8.8.0 through 8.8.7, 8.9.0, and 9.0.0 allows remote authenticated users to alter protected fields. The JSON:API module accepts PATCH requests for certain fields without enforcing their validation constraints. Exploitation requires JSON:API read/write mode, with jsonapi.settings read_only set to FALSE; the default read-only mode blocks the write.

The record

CVE
CVE-2020-13665
Published
May 5, 2021
Updated
Aug 4, 2024
Vendor
Drupal
Product
Drupal Core
Classifications
CWE-863
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. May 5, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=8.8.x <8.8.8
  2. Affected versionversion=8.9.x <8.9.1
  3. Affected versionversion=9.0.x <9.0.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Drupal · Drupal Coreversion=8.8.x <8.8.8; version=8.9.x <8.9.1; version=9.0.x <9.0.1

Published CVSS scores

9.8GitHub Advisory DatabaseCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-863Incorrect Authorization

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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