CVE-2023-7080: Arbitrary remote code execution within `wrangler dev` Workers sandbox

Should you act?

Normal patch cycle

No exploitation signal; fix it in your next routine update if you are affected. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.

• No confirmed exploitation. It is not in CISA’s KEV catalog. That can change quickly after a public write-up; re-check if you are affected.
• EPSS 0.6%, percentile 49: FIRST’s model estimates a 0.6% chance of exploitation activity in the next 30 days, higher than 49% of all scored CVEs (low). EPSS is a probability, not a verdict.
• Needs a user to click or open something. Phishing makes that realistic, but it is not wormable.
• Only applies if your dependency tree includes wrangler (npm) >= 3.0.0, < 3.19.0, fixed in 3.19.0; wrangler (npm) >= 2.0.0, < 2.20.2, fixed in 2.20.2. Check your lockfile, including transitive dependencies.

What it is

The V8 inspector intentionally allows arbitrary code execution within the Workers sandbox for debugging. wrangler dev would previously start an inspector server listening on all network interfaces. This would allow an attacker on the local network to connect to the inspector and run arbitrary code. Additionally, the inspector server did not validate Origin/Host headers, granting an attacker that can trick any user on the local network into opening a malicious website the ability to run code. If wrangler dev --remote was being used, an attacker could access production resources if they were bound to the worker. This issue was fixed in wrangler@3.19.0 and wrangler@2.20.2. Whilst wrangler dev's inspector server listens on local interfaces by default as of wrangler@3.16.0, an SSRF vulnerability in miniflare https://github.com/cloudflare/workers-sdk/security/advisories/GHSA-fwvg-2739-22v7 (CVE-2023-7078) allowed access from the local network until wrangler@3.18.0. wrangler@3.19.0 and wrangler@2.20.2 introduced validation for the Origin/Host headers.

From the GitHub advisory

Impact The V8 inspector intentionally allows arbitrary code execution within the Workers sandbox for debugging. wrangler dev would previously start an inspector server listening on all network interfaces. This would allow an attacker on the local network to connect to the inspector and run arbitrary code. Additionally, the inspector server did not validate Origin/Host headers, granting an attacker that can trick any user on the local network into opening a malicious website the ability to run code. If wrangler dev --remote was being used, an attacker could access production resources if they were bound to the worker.

Patches This issue was fixed in wrangler@3.19.0 and wrangler@2.20.2. Whilst wrangler dev's inspector server listens on local interfaces by default as of wrangler@3.16.0, an SSRF vulnerability in miniflare allowed access from the local network until wrangler@3.18.0. wrangler@3.19.0 and wrangler@2.20.2 introduced validation for the Origin/Host headers.

Workarounds Unfortunately, Wrangler doesn't provide any configuration for which host that inspector server should listen on. Please upgrade to at least wrangler@3.16.0, and configure Wrangler to listen on local interfaces instead with wrangler dev --ip 127.0.0.1 to prevent SSRF. This removes the local network as an attack vector, but does not prevent an attack from visiting a malicious website.

References - https://github.com/cloudflare/workers-sdk/issues/4430 - https://github.com/cloudflare/workers-sdk/pull/4437 - https://github.com/cloudflare/workers-sdk/pull/4535 - https://github.com/cloudflare/workers-sdk/pull/4550

Weakness type: CWE-269.

Product: wrangler (npm) · Assigned by: cloudflare · Published: 2023-12-29

Affected and fixed versions

Severity scores

• Attack vector: adjacent network only
• Attack complexity: low
• Privileges required: none (no login)
• User interaction: required (a user must click/open something)
• Scope: changed (can affect other components)

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).
• FIRST EPSS (model of 2026-10-21): 0.63% probability of exploitation activity in the next 30 days; percentile 49.

Timeline

• 2023-12-29 — CVE record published by cloudflare
• 2024-01-03 — GitHub-reviewed advisory GHSA-f8mp-x433-5wpf published (critical)
• 2024-08-02 — CVE record last updated

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-f8mp-x433-5wpf github.com
2. CVE.org record CVE-2023-7080 cve.org
3. NVD entry CVE-2023-7080 nvd.nist.gov

Other references from the CVE record and advisory

1. github.com github.com
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4. github.com github.com
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7. github.com github.com
8. github.com github.com
9. github.com github.com

Critical npm advisories · Today’s Security Digest