Drupal Core Remote Code Execution
CVE-2019-6340 is a high-severity deserialization of untrusted data vulnerability in Drupal Core from Drupal, with a CVSS 3.1 base score of 8.1 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists versions 8.5.11, 8.6.10 as the first without the flaw, so updating Drupal Core to one of those releases or later removes the exposure. CISA added it to the Known Exploited Vulnerabilities catalogue on March 25, 2022, which means attacks have been observed in the wild.
Attackers are already exploiting this vulnerability, according to CISA.
What to do
- Update Drupal Core to 8.5.11 or 8.6.10, whichever matches your release line, or a later version.
- Update Drupal to 8.5.11 or 8.6.10, whichever matches your release line, or a later version.
- CISA's required action: Apply updates per vendor instructions.
- Read the advisory on drupal.org for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Drupal | Drupal Core | 8.5 up to, but not including, 8.5.11; 8.6 up to, but not including, 8.6.10 | 8.5.11, 8.6.10 |
| Drupal | Drupal | 8.5.0 up to, but not including, 8.5.11; 8.6.0 up to, but not including, 8.6.10 | 8.5.11, 8.6.10 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- HighSuccess depends on conditions outside the attacker's control.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 8.1 | High | NVD |
| CVSS 3.1 | 8.1 | High | CISA (ADP) |
| CVSS 2.0 | 6.8 | Medium | NVD |
Official description
Some field types do not properly sanitize data from non-form sources in Drupal 8.5.x before 8.5.11 and Drupal 8.6.x before 8.6.10. This can lead to arbitrary PHP code execution in some cases. A site is only affected by this if one of the following conditions is met: The site has the Drupal 8 core RESTful Web Services (rest) module enabled and allows PATCH or POST requests, or the site has another web services module enabled, like JSON:API in Drupal 8, or Services or RESTful Web Services in Drupal 7. (Note: The Drupal 7 Services module itself does not require an update at this time, but you should apply other contributed updates associated with this advisory if Services is in use.)
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Deserialization of Untrusted Data
The product deserializes untrusted data without sufficiently ensuring that the resulting data will be valid.
How developers prevent this class of flaw
- If available, use the signing/sealing features of the programming language to assure that deserialized data has not been tainted. For example, a hash-based message authentication code (HMAC) could be used to ensure that data has not been modified.
- When deserializing data, populate a new object rather than just deserializing. The result is that the data flows through safe input validation and that the functions are safe.
- Explicitly define a final object() to prevent deserialization.
More Deserialization of Untrusted Data vulnerabilities (CWE-502)
Timeline
- CVE record published.
- Added to CISA's Known Exploited Vulnerabilities catalogue.
- Deadline for US federal agencies to remediate, set by CISA.
- CISA published its SSVC assessment (exploitation: active, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Advisories
- drupal.org/sa-core-2019-003Mitigation
Patches and release notes
- exploit-db.com/exploits/46452/Third Party Advisory, VDB Entry
Third-party and government advisories
- synology.com/security/advisory/Synology_SA_19_09Third Party Advisory
- cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2019-6340US Government Resource
Technical write-ups (may include proof of concept)
- exploit-db.com/exploits/46459/Exploit, Third Party Advisory, VDB Entry
- exploit-db.com/exploits/46510/Exploit, Third Party Advisory
Other vulnerabilities in Drupal Core
- 8.1 High severity
- 9.8 Critical severity
Drupal Core SQL Injection Exploited
- 7.5 High severity
- 9.8 Critical severity
- 9.8 Critical severity
- 9.8 Critical severity
Recent Deserialization of Untrusted Data vulnerabilities
- 9.8 Critical severity
- 8.1 High severity
- 9.8 Critical severity
- 8.8 High severity
- 9.8 Critical severity
Oracle WebLogic Server Unspecified Exploited
- 9.8 Critical severity
Spotted an error? Tell us.