Backdrop: Incomplete Cleanup
CVE-2026-107914 is a high-severity incomplete cleanup vulnerability in Backdrop from BackdropCMS, with a CVSS 3.1 base score of 7.8 out of 10. It can be exploited with local access to the system by an unauthenticated attacker, without any action from a user. The record lists versions 1.34.5, 1.35.1 as the first without the flaw, so updating Backdrop to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.12% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Backdrop to 1.34.5 or 1.35.1, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Backdropcms | Backdrop | 1.34.0 up to, but not including, 1.34.5; 1.35.0 up to, but not including, 1.35.1 | 1.34.5, 1.35.1 |
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
- LocalThe attacker needs local access or must trick a user into running something.
- 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
- ChangedThe attack can reach beyond the vulnerable component into other systems.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- NoneAvailability is not affected.
Vector: CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:N. Scored by CNA (mitre.org).
Official description
Backdrop CMS 1.34 before 1.34.5 and 1.35 before 1.35.1 doesn't sufficiently protect configuration exports when delivering a compressed archive. This vulnerability is mitigated by the fact that an export must have been previously requested by someone with the "Synchronize, import, and export configuration" permission. NOTE: CVE-2026-107914 refers to the vulnerability in which config.admin.inc does not ensure that a file_unmanaged_delete operation occurs. Therefore, many archives could persist: config.tar.gz, config_0.tar.gz, config_1.tar.gz, etc. There is a separate config.module issue that could allow remote access by an anonymous user, but only for the one filename config.tar.gz.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Incomplete Cleanup
The product does not properly clean up and remove temporary or supporting resources after they have been used.
How developers prevent this class of flaw
- Temporary files and other supporting resources should be deleted/released immediately after they are no longer needed.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
Other references
Other vulnerabilities in Backdrop
- 7.5 High severity
Recent Incomplete Cleanup vulnerabilities
- 9.6 Critical severity
- 9.1 Critical severity
- 8.8 High severity
- 8.4 High severity
- 9.0 Critical severity
- 7.3 High severity
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