Unrated

SSRF protection bypass in ToolHive NAT64/DNS64 handling

IdentifiersCVE-2026-54450CWE-918

CVE-2026-54450 is a server-side request forgery protection bypass in ToolHive. The vulnerability stems from incomplete validation of destination addresses in the product's private and reserved IP filtering logic: the guard does not correctly recognize IPv6 NAT64 ranges and therefore fails to identify embedded private, loopback, link-local, and other reserved IPv4 destinations when they are represented through NAT64 addressing in NAT64/DNS64 environments. As a result, attacker-controlled URLs processed by guarded HTTP client functionality, including the embedded OAuth authorization server's CIMD fetch path, can induce ToolHive to initiate outbound connections to internal or otherwise restricted network targets that should have been blocked by the SSRF defense.

For your environment

Are you exposed to this one?

Mallory correlates every CVE against your assets, your vendors, and active adversary campaigns. Know which vulnerabilities matter for you, not just which ones are loud.

Start free trial

ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

What an attacker gets, and what they’ve been doing with it.

Successful exploitation allows an attacker to bypass ToolHive's SSRF restrictions and trigger blind outbound requests from the vulnerable instance to internal, loopback, RFC1918, link-local, or cloud metadata-style destinations reachable through NAT64 translation. The practical impact is primarily internal network reachability testing, SSRF reconnaissance, and limited probing of protected services. Reported impact is constrained by HTTPS-only behavior, TLS certificate validation, and the absence of response reflection on the relevant request path, which reduces the likelihood of direct response disclosure, metadata extraction, or credential theft through this vector alone.

Mitigation

If you can’t patch tonight, do this now.

If immediate patching is not possible, avoid deploying ToolHive in NAT64/DNS64 environments where attacker-supplied URLs can reach the vulnerable HTTP client path. Restrict or disable exposure of the embedded OAuth authorization server's CIMD functionality to untrusted external users. Apply network-layer egress controls and segmentation to prevent ToolHive from reaching internal, link-local, loopback, and metadata-service destinations, and enforce filtering that blocks access to sensitive internal services through NAT64-translated address space.

Remediation

Patch, then assume compromise.

Upgrade ToolHive to version 0.29.1 or later. The fix adds explicit handling for NAT64 prefixes, including 64:ff9b::/96 and 64:ff9b:1::/48, and applies private and reserved IPv4 checks to embedded addresses or blocks unresolved cases fail-closed. Validate that all deployments use the corrected release and that any custom SSRF filtering logic or downstream forks incorporate equivalent NAT64-aware destination validation.

PUBLIC EXPLOITS

Exploits

No public exploits tracked yet. Mallory keeps watching.

VALID 0 / 0 TOTALView more in app

No public exploit code observed for this vulnerability.

EXPOSURE SURFACE

Affected products & vendors

Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.

VendorProductType

StacklokToolhiveapplication

Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.

ACTIVITY FEED

Recent activity

No public activity tracked yet. Mallory keeps watching.

0 SOURCESView more in app

No public activity observed for this vulnerability.

What this page doesn’t show

The version that knows your environment.

This page is what’s public. Mallory adds the parts that aren’t: which of your assets are affected, which adversaries are exploiting it right now, which detections to deploy, and what to do tonight.

Start free trial

Exposure mapping

Query your assets running an affected version, and investigate the blast radius.

Threat actor evidence

Every observed campaign linking this CVE to a named adversary.

Associated malware

Malware families riding this exploit, with evidence and IOCs.

Detection signatures

YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.

Vendor-by-vendor mapping

Cross-references every affected SKU, including bundled OEM variants.

Social activity