CVE-2026-61742: DBHub HTTP transport DNS rebinding allows unauthenticated browser-origin SQL execution

Should you act?

Critical and remotely reachable

No known exploitation yet, but it is network-reachable without credentials. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.

• Not in CISA KEV, but CISA’s SSVC assessment records a public proof-of-concept, so attack code exists.
• EPSS 0.2%, percentile 9: FIRST’s model estimates a 0.2% chance of exploitation activity in the next 30 days, higher than 9% of all scored CVEs (low). EPSS is a probability, not a verdict.
• Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
• Only applies if your dependency tree includes @bytebase/dbhub (npm) <= 0.22.4, fixed in 0.22.5. Check your lockfile, including transitive dependencies.

What it is

DBHub is a database MCP server for Postgres, MySQL, SQL Server, Oracle, MariaDB, SQLite. Versions prior to 0.22.5 expose an unauthenticated HTTP MCP endpoint when started with the documented HTTP transport mode, for example --transport http --port 8080. The HTTP server attempts to protect browser-origin access by checking whether the Origin hostname equals the Host hostname, then reflecting the validated Origin into Access-Control-Allow-Origin. This does not stop DNS rebinding. After an attacker-controlled hostname rebinds to a victim-accessible DBHub HTTP server, both Origin and Host can contain the attacker-controlled hostname, so DBHub accepts the request and dispatches MCP tool calls. As a result, a malicious website can deterministically invoke DBHub MCP tools from the victim's browser without prompt injection or model involvement. With the default demo configuration this can read and write the demo SQLite database; with a real configured database, the same primitive can read, enumerate, and potentially write database contents depending on DBHub's configured tool permissions and database credentials. Version 0.22.5 fixes the issue.

From the GitHub advisory

Summary

DBHub 0.21.2 exposes an unauthenticated HTTP MCP endpoint when started with the documented HTTP transport mode, for example --transport http --port 8080.

The HTTP server attempts to protect browser-origin access by checking whether the Origin hostname equals the Host hostname, then reflecting the validated Origin into Access-Control-Allow-Origin. This does not stop DNS rebinding. After an attacker-controlled hostname rebinds to a victim-accessible DBHub HTTP server, both Origin and Host can contain the attacker-controlled hostname, so DBHub accepts the request and dispatches MCP tool calls.

As a result, a malicious website can deterministically invoke DBHub MCP tools from the victim's browser without prompt injection or model involvement. With the default demo configuration this can read and write the demo SQLite database; with a real configured database, the same primitive can read, enumerate, and potentially write database contents depending on DBHub's configured tool permissions and database credentials.

Recommended severity: High. It may become Critical when HTTP transport is connected to production or broadly privileged database credentials.

Weakness type: CWE-306, CWE-346.

Product: @bytebase/dbhub (npm) · Assigned by: GitHub_M · Published: 2026-09-24

Affected and fixed versions

Severity scores

• Attack vector: network (remotely reachable)
• Attack complexity: low
• Attack requirements: none
• Privileges required: none (no login)
• User interaction: none

CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.

Exploitation and urgency

• CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
• CISA SSVC assessment: exploitation poc, automatable yes, technical impact total.
• FIRST EPSS (model of 2026-10-21): 0.20% probability of exploitation activity in the next 30 days; percentile 9.

Timeline

• 2026-09-24 — CVE record last updated
• 2026-09-24 — CVE record published by GitHub_M
• 2026-09-24 — GitHub-reviewed advisory GHSA-fm8p-53ww-hf6w published (critical)

Sources and references

Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.

Vulnerability records

1. GitHub Advisory GHSA-fm8p-53ww-hf6w github.com
2. CVE.org record CVE-2026-61742 cve.org
3. NVD entry CVE-2026-61742 nvd.nist.gov

Other references from the CVE record and advisory

1. github.com github.com
2. github.com github.com
3. github.com github.com
4. github.com github.com

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