Tooling: Exposure of Data Element to Wrong Session
CVE-2026-16498 is a critical-severity exposure of data element to wrong session vulnerability in Tooling from HashiCorp, with a CVSS 3.1 base score of 10.0 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists version 1.1.0 as the first without the flaw, so updating Tooling to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.46% chance of exploitation within 30 days, which is low compared with other CVEs.
Critical severity: a successful attack would have severe impact.
What to do
- Update Tooling to 1.1.0 or a later version.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
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
- 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
- LowPerformance or availability is reduced.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:L. Scored by CNA (hashicorp.com).
Official description
The terraform-mcp-server before version 1.1.0 is vulnerable to a cross-tenant credential reuse issue in the streamable-HTTP stateless transport mode that may allow one user's Terraform token to be used to execute tool calls on behalf of subsequent users. This vulnerability, CVE-2026-16498, is fixed in terraform-mcp-server 1.1.0.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Exposure of Data Element to Wrong Session
The product does not sufficiently enforce boundaries between the states of different sessions, causing data to be provided to, or used by, the wrong session.
How developers prevent this class of flaw
- Protect the application's sessions from information leakage. Make sure that a session's data is not used or visible by other sessions.
- Use a static analysis tool to scan the code for information leakage vulnerabilities (e.g. Singleton Member Field).
- In a multithreading environment, storing user data in Servlet member fields introduces a data access race condition. Do not use member fields to store information in the Servlet.
More Exposure of Data Element to Wrong Session vulnerabilities (CWE-488)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Other references
Other vulnerabilities in Tooling
- 9.9 Critical severity
- 7.7 High severity
- 9.6 Critical severity
- 8.6 High severity
- 10.0 Critical severity
- 8.9 High severity
Recent Exposure of Data Element to Wrong Session vulnerabilities
- 7.7 High severity
- 7.5 High severity
- 9.1 Critical severity
- 8.3 High severity
- 7.5 High severity
- 7.5 High severity
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