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CVE-2026-47356: Tenable Terrascan Server Side Request Forgery (CVSS 8.7)

CVE-2026-47356 is a high severity server side request forgery in Tenable Terrascan with a CVSS score of 8.7. Apply the vendor fix and confirm exposure on internet facing and business critical assets first.

Last updated: Jul 24, 2026

Quick answer

Direct answer

CVE-2026-47356 is a high severity server side request forgery in Tenable Terrascan with a CVSS score of 8.7. Apply the vendor fix and confirm exposure on internet facing and business critical assets first.

Risk scores

CVSS base score
8.7HIGH
EPSS probability
0.61%
Higher than 48 percent of all CVEs
CISA KEV
Not listed
CVSS metricWhat it means
Attack vector (AV:N)Network: reachable remotely
Attack complexity (AC:L)Low complexity
Attack requirements (AT:N)No attack requirements
Privileges required (PR:N)No privileges required
User interaction (UI:N)No user interaction
Confidentiality (VC:H)High confidentiality impact
Integrity (VI:N)No integrity impact
Availability (VA:N)No availability impact

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:L/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

About Tenable Terrascan

CVE-2026-47356 affects Tenable Terrascan, a product from Tenable. Before acting, confirm where Tenable Terrascan runs in your estate, who owns it and whether it is reachable from the internet, because exposure decides real risk more than the score alone.

What the flaw is

In plain terms: Terrascan v1.18.3 and prior are vulnerable to Server-Side Request Forgery (SSRF) via the webhook_url parameter in the file scan endpoint (POST /v1/{iac}/{iacVersion}/{cloud}/local/file/scan) when running in server mode. An unauthenticated remote attacker can supply an arbitrary URL as the webhook_url multipart form parameter. After scanning the uploaded file, Terrascan sends an HTTP POST request to the attacker-controlled URL containing the full scan results as a JSON body, with the attacker-supplied webhook_token forwarded as a Bearer token in the Authorization header. The retryable HTTP client retries up to 10 times on failure. This affects deployments running terrascan in server mode (terrascan server), which binds to 0.0.0.0 with no authentication. Note: Terrascan was archived in August 2023 and no patch will be released.

The weakness class is Server Side Request Forgery. The server can be made to send requests to internal or arbitrary systems.

Based on its CVSS vector, the flaw can be reached over the network, needs no login, and needs no user interaction. Apply the vendor fix and confirm exposure on internet facing and business critical assets first.

Affected versions and timeline

FieldDetail
ProductTenable Terrascan
Affected versionsTerrascan up to and including 1.18.3
PublishedMay 19, 2026
Last modifiedJul 24, 2026
Added to CISA KEVNot listed
Assigning CNAvulnreport@tenable.com

How to detect it

  • Inventory every instance of Tenable Terrascan and record the running version against the affected range above.
  • Check external attack surface scans for internet facing instances of the component.
  • Review logs on affected systems for unusual requests, errors or new processes around the vulnerable function.
  • Confirm with an authenticated vulnerability scan once your scanner has a check for this CVE.

How to fix it

  • Apply the fixed version of Tenable Terrascan named in the vendor advisory.
  • If patching must wait, restrict network access to the affected service and put it behind authentication or a web application firewall rule.
  • Rescan after the change to prove the exposure is gone, then close the ticket.

CTEM action plan

CTEM stageWhat to do for this CVE
ScopeAdd every business service that depends on Tenable Terrascan to the current CTEM cycle.
DiscoverFind all instances, including shadow and cloud deployments, and record versions and exposure.
PrioritizeRank using EPSS and CVSS together with asset exposure and business impact.
ValidateConfirm the flaw is reachable and exploitable in your environment and that compensating controls work.
MobilizeAssign the fix to the asset owner with a due date matched to the priority, then verify closure.

CWE References

Technical References

Frequently asked questions

CVE-2026-47356 is a high severity server side request forgery in Tenable Terrascan with a CVSS score of 8.7. Apply the vendor fix and confirm exposure on internet facing and business critical assets first.

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Terrascan v1.18.3 and prior are vulnerable to Server-Side Request Forgery (SSRF) via external URL resolution in uploaded IaC templates when running in server mode. When Terrascan parses uploaded ARM templates or CloudFormation templates, it resolves external URLs referenced within those templates via hashicorp/go-getter with all default detectors enabled, including FileDetector. An unauthenticated remote attacker can upload an ARM template containing a templateLink.uri or parametersLink.uri field, or a CloudFormation template containing an AWS::CloudFormation::Stack TemplateURL field, pointing to an attacker-controlled URL. Terrascan will fetch the attacker-controlled URL server-side. Unlike SSRF via the remote scan endpoint, file:// URLs are directly usable without requiring an X-Terraform-Get redirect, enabling local file read. This affects deployments running terrascan in server mode (terrascan server), which binds to 0.0.0.0 with no authentication. Note: Terrascan was archived in August 2023 and no patch will be released.

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