Confluence Data Center: Asymmetric Resource Consumption (Amplification)
CVE-2025-22166 is a high-severity asymmetric resource consumption (amplification) vulnerability in Confluence Data Center from Atlassian, with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected Confluence Data Center versions: 9.5.1 to 9.5.4; 9.4.0 to 9.4.1; 9.3.1 to 9.3.2, and others listed below. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.52% 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 Confluence Server to 8.5.25 or 9.2.7 or 10.0.2, whichever matches your release line, or a later version.
- Read the advisory on confluence.atlassian.com 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 |
|---|---|---|---|
| Atlassian | Confluence Data Center | 9.5.1 to 9.5.4; 9.4.0 to 9.4.1; 9.3.1 to 9.3.2; 9.2.0 to 9.2.6; 9.1.0 to 9.1.1; 9.0.1 to 9.0.3; 8.9.0 to 8.9.8; 8.8.0 to 8.8.1; and 4 more ranges | Not stated |
| Atlassian | Confluence Server | 8.5.0 up to, but not including, 8.5.25; 9.2.0 up to, but not including, 9.2.7; 10.0.0 up to, but not including, 10.0.2 | 8.5.25, 9.2.7, 10.0.2 |
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
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- NoneNo data is disclosed.
- Integrity
- NoneNothing can be modified.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 4.0 | 8.3 | High | CNA (atlassian.com) |
| CVSS 3.1 | 7.5 | High | NVD |
Official description
This High severity DoS (Denial of Service) vulnerability was introduced in version 2.0 of Confluence Data Center. This DoS (Denial of Service) vulnerability, with a CVSS Score of 8.3, allows an attacker to cause a resource to be unavailable for its intended users by temporarily or indefinitely disrupting services of a host connected to a network. Atlassian recommends that Confluence Data Center customers upgrade to latest version, if you are unable to do so, upgrade your instance to one of the specified supported fixed versions: Confluence Data Center and Server 8.5: Upgrade to a release greater than or equal to 8.5.25 Confluence Data Center and Server 9.2: Upgrade to a release greater than or equal to 9.2.7 Confluence Data Center and Server 10.0: Upgrade to a release greater than or equal to 10.0.2 See the release notes ([https://confluence.atlassian.com/doc/confluence-release-notes-327.html]). You can download the latest version of Confluence Data Center from the download center ([https://www.atlassian.com/software/confluence/download-archives]). This vulnerability was reported via our Atlassian (Internal) program.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Asymmetric Resource Consumption (Amplification)
The product does not properly control situations in which an adversary can cause the product to consume or produce excessive resources without requiring the adversary to invest equivalent work or otherwise prove authorization, i.e., the adversary's influence is asymmetric.
How developers prevent this class of flaw
- An application must make resources available to a client commensurate with the client's access level.
- An application must, at all times, keep track of allocated resources and meter their usage appropriately.
- Consider disabling resource-intensive algorithms on the server side, such as Diffie-Hellman key exchange.
More Asymmetric Resource Consumption (Amplification) vulnerabilities (CWE-405)
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 Confluence Data Center
- 7.5 High severity
- 7.1 High severity
- 7.1 High severity
- 9.3 Critical severity
- 7.5 High severity
- 8.2 High severity
Recent Asymmetric Resource Consumption (Amplification) vulnerabilities
- 9.8 Critical severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
- 7.4 High severity
Spotted an error? Tell us.