Zammad: Client-Side Enforcement of Server-Side Security
CVE-2025-32359 is a high-severity client-side enforcement of server-side security vulnerability in Zammad, with a CVSS 3.1 base score of 8.8 out of 10. It can be exploited remotely over the network by an attacker with a low-privileged account, without any action from a user. The record lists version 6.4.2 as the first without the flaw, so updating Zammad to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.3% 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 Zammad to 6.4.2 or a later version.
- Read the advisory on zammad.com for workarounds and exact fixed builds.
Affected products and versions
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
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- LowA basic user account is enough.
- 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:L/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 4.8 | Medium | CNA (mitre.org) |
| CVSS 3.1 | 8.8 | High | NVD |
Official description
In Zammad 6.4.x before 6.4.2, there is client-side enforcement of server-side security. When changing their two factor authentication configuration, users need to re-authenticate with their current password first. However, this change was enforced in Zammad only on the front end level, and not when using the API directly.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Client-Side Enforcement of Server-Side Security
The product includes a server that relies on the client to implement a protection mechanism that is intended to protect the server.
How developers prevent this class of flaw
- If some degree of trust is required between the two entities, then use integrity checking and strong authentication to ensure that the inputs are coming from a trusted source. Design the product so that this trust is managed in a centralized fashion, especially if there are complex or numerous communication channels, in order to reduce the risks that the implementer will mistakenly omit a check in a single code path.
More Client-Side Enforcement of Server-Side Security vulnerabilities (CWE-602)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Advisories
Other vulnerabilities in Zammad
- 7.8 High severity
- 9.8 Critical severity
Zammad GmbH Zammad Session Fixation Exploited
- 7.1 High severity
- 7.1 High severity
- 9.1 Critical severity
- 8.6 High severity
Recent Client-Side Enforcement of Server-Side Security vulnerabilities
- 8.8 High severity
- 8.8 High severity
- 8.8 High severity
- 8.8 High severity
- 7.8 High severity
- 7.8 High severity
Spotted an error? Tell us.