@budibase/backend-core has potential SSRF DNS rebinding bypass in outbound fetch validation (CVE-2026-54353)
Authenticated users with automation permissions in Budibase backend-core versions prior to 3.39.9 can exploit a Server-Side Request Forgery (SSRF) vulnerability via DNS rebinding. The vulnerability arises because the hostname validation and the actual DNS resolution for outbound fetch requests are performed separately, allowing an attacker-controlled hostname to resolve to a public IP during validation and a private/internal IP during the actual connection. This enables non-blind SSRF attacks against internal services including loopback, RFC1918 ranges, and cloud metadata endpoints. The vulnerability affects multiple automation steps that perform outbound fetches, potentially exposing sensitive internal resources and cloud credentials.
AI Analysis
Technical Summary
The vulnerability in @budibase/backend-core (CVE-2026-54353) is a DNS rebinding SSRF bypass affecting the outbound fetch validation flow. The system validates hostnames against a blacklist by resolving DNS once, but the actual socket connection performs a separate DNS lookup via node-fetch, which is not pinned to the validated IPs. An attacker controlling DNS can return a public IP during validation to bypass the blacklist and then a private/internal IP during the real connection, enabling SSRF to internal services such as loopback, private networks, Kubernetes/VPC services, and cloud metadata endpoints. This affects various automation steps including outgoing webhooks and integrations with Slack, Discord, and others. The vulnerability allows non-blind SSRF, as some steps return upstream response content directly in automation outputs. The issue is due to a classic TOCTOU DNS rebinding problem in the validation and fetch implementation.
Potential Impact
Successful exploitation allows authenticated users with automation permissions to perform SSRF attacks against internal network resources accessible from the Budibase host. This includes access to loopback interfaces (127.0.0.1), private IP ranges (RFC1918), internal Kubernetes or VPC services, and cloud metadata endpoints (169.254.169.254). On cloud deployments without IMDSv2 enforcement, attackers may retrieve temporary IAM credentials from metadata endpoints. In multi-tenant hosted environments, this could lead to cross-tenant access via shared internal infrastructure. The SSRF is non-blind, meaning response data from internal services can be directly observed in automation outputs, increasing the risk and ease of exploitation.
Mitigation Recommendations
A patch is available for this vulnerability. Users should upgrade @budibase/backend-core to version 3.39.9 or later where the issue is fixed. Until patched, avoid granting automation permissions to untrusted users and restrict access to the affected automation features. The vendor advisory confirms the availability of an official fix. No alternative mitigations are specified in the advisory.
@budibase/backend-core has potential SSRF DNS rebinding bypass in outbound fetch validation (CVE-2026-54353)
Description
Authenticated users with automation permissions in Budibase backend-core versions prior to 3.39.9 can exploit a Server-Side Request Forgery (SSRF) vulnerability via DNS rebinding. The vulnerability arises because the hostname validation and the actual DNS resolution for outbound fetch requests are performed separately, allowing an attacker-controlled hostname to resolve to a public IP during validation and a private/internal IP during the actual connection. This enables non-blind SSRF attacks against internal services including loopback, RFC1918 ranges, and cloud metadata endpoints. The vulnerability affects multiple automation steps that perform outbound fetches, potentially exposing sensitive internal resources and cloud credentials.
CVSS v3.1
Score 8.5high
Affected software
Run on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The vulnerability in @budibase/backend-core (CVE-2026-54353) is a DNS rebinding SSRF bypass affecting the outbound fetch validation flow. The system validates hostnames against a blacklist by resolving DNS once, but the actual socket connection performs a separate DNS lookup via node-fetch, which is not pinned to the validated IPs. An attacker controlling DNS can return a public IP during validation to bypass the blacklist and then a private/internal IP during the real connection, enabling SSRF to internal services such as loopback, private networks, Kubernetes/VPC services, and cloud metadata endpoints. This affects various automation steps including outgoing webhooks and integrations with Slack, Discord, and others. The vulnerability allows non-blind SSRF, as some steps return upstream response content directly in automation outputs. The issue is due to a classic TOCTOU DNS rebinding problem in the validation and fetch implementation.
Potential Impact
Successful exploitation allows authenticated users with automation permissions to perform SSRF attacks against internal network resources accessible from the Budibase host. This includes access to loopback interfaces (127.0.0.1), private IP ranges (RFC1918), internal Kubernetes or VPC services, and cloud metadata endpoints (169.254.169.254). On cloud deployments without IMDSv2 enforcement, attackers may retrieve temporary IAM credentials from metadata endpoints. In multi-tenant hosted environments, this could lead to cross-tenant access via shared internal infrastructure. The SSRF is non-blind, meaning response data from internal services can be directly observed in automation outputs, increasing the risk and ease of exploitation.
Mitigation Recommendations
A patch is available for this vulnerability. Users should upgrade @budibase/backend-core to version 3.39.9 or later where the issue is fixed. Until patched, avoid granting automation permissions to untrusted users and restrict access to the affected automation features. The vendor advisory confirms the availability of an official fix. No alternative mitigations are specified in the advisory.
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- GHSA-gfq7-5x4g-3xhf
- Osv Schema Version
- 1.4.0
- Aliases
- ["CVE-2026-54353"]
- Ecosystems
- ["npm"]
- Database Specific Severity
- HIGH
- Cvss Version
- 3.1
Threat ID: 6a7cd3e1bf8831d53917fe53
Added to database: 08/12/2026, 20:13:21 UTC
Last enriched: 08/12/2026, 20:57:00 UTC
Last updated: 09/25/2026, 13:47:46 UTC
Views: 23
Community Reviews
0 reviewsCrowdsource mitigation strategies, share intel context, and vote on the most helpful responses. Sign in to add your voice and help keep defenders ahead.
Want to contribute mitigation steps or threat intel context? Sign in or create an account to join the community discussion.
Actions
Updates to AI analysis require Pro Console access. Upgrade inside Console → Billing.
Need more coverage?
Upgrade to Pro Console for AI refresh and higher limits.
For incident response and remediation, OffSeq services can help resolve threats faster.
Latest Threats
Check if your credentials are on the dark web
Instant breach scanning across billions of leaked records. Free tier available.