wazuh: Deserialization of Untrusted Data
CVE-2026-28220 is a critical-severity deserialization of untrusted data vulnerability in wazuh, with a CVSS 3.1 base score of 9.1 out of 10. It can be exploited remotely over the network by an attacker with administrator privileges, without any action from a user. Affected wazuh versions: >= 4.0.0, < 4.14.5. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.66% chance of exploitation within 30 days, higher than 52% of scored CVEs.
Critical severity: a successful attack would have severe impact.
What to do
- Check which version of wazuh you run against the affected versions below, and install the vendor's latest release.
- Read the advisory on github.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
- HighAdministrator-level access is required first.
- 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
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 8.4 | High | CNA (github.com) |
| CVSS 3.1 | 9.1 | Critical | NVD |
Official description
Wazuh is a free and open source platform used for threat prevention, detection, and response. Prior to version 4.14.5, issues in the Cluster Distributed API (DAPI) handling allow a cluster peer, or any actor able to authenticate to the cluster channel using the shared cluster key, to make the master node deserialize an attacker-controlled callable and execute it under an attacker-controlled RBAC context. The cluster code in `framework/wazuh/core/cluster/common.py` deserializes JSON with `as_wazuh_object()`, which resolves any callable whose top-level package is wazuh or api (an overly broad allowlist controlled only by `ALLOWED_CALLABLES_PACKAGES`), and DAPI requests handled in framework/wazuh/core/cluster/dapi/dapi.py accept a client-supplied rbac_permissions value that `run_local()` applies as the global RBAC context, so supplying an rbac_mode of black causes authorization checks for expose_resources-protected functions to pass without any legitimate permission assignment. Combined, these allow privileged administrative actions on the master node such as arbitrary file writes under WAZUH_PATH, creation of new API users, and tampering with security.yaml, and can be chained into full manager compromise. This issue has been fixed in version 4.14.5.
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.
- CISA published its SSVC assessment (exploitation: poc, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Advisories
Other vulnerabilities in wazuh
- 7.5 High severity
- 9.1 Critical severity
- 7.1 High severity
- 8.1 High severity
- 9.1 Critical severity
- 9.1 Critical severity
Recent Deserialization of Untrusted Data vulnerabilities
- 9.8 Critical severity
- 7.8 High severity
- 9.9 Critical severity
- 8.0 High severity
- 9.1 Critical severity
- 8.1 High severity
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