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Response snapshot Nov 5, 2026, 23:11 UTC

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VulnerabilityCVE-2026-63188

logto-tunnel serves files outside `--experience-path` via path traversal

@logto/tunnel serves custom sign-in experience files from the --experience-path directory. When the tunnel service is reachable, a requester can use ../ path segments in a static asset request to read files outside that directory that the CLI process can read.

At a glance

Exploited
Not known
Severity
8.7 High (CVSS 4.0)
Chance of exploitation
0.5% in the next 30 days
Sources
1 source

What to do

GitHub lists first patched versions: @logto/tunnel: 0.3.9. Confirm the affected range and upgrade guidance in the exact advisory.

Read GitHub-reviewed advisory GHSA-rxjr-6c9q-h67x (opens a new tab)

What happened

Summary

@logto/tunnel serves custom sign-in experience files from the --experience-path directory. When the tunnel service is reachable, a requester can use ../ path segments in a static asset request to read files outside that directory that the CLI process can read.

Details

The tunnel command accepts --experience-path as the local folder path for custom sign-in experience assets. packages/tunnel/src/commands/tunnel/index.ts enables createStaticFileProxy(path) when that option is set and sends non-Logto, non---experience-uri requests to that static proxy. The server is started with server.listen(port).

Continue reading

packages/tunnel/src/commands/tunnel/utils.ts builds the filesystem path as path.join(staticPath, fallBackToIndex ? index : request.url). For file asset paths, request.url is used directly. A request URL such as /../secret.txt resolves outside staticPath and is then opened with fs.open(requestPath, 'r'). There is no URL normalization and no containment check that the resolved path remains under the configured static directory before the file is read and returned.

The proof boundary is the packaged CLI end-to-end run. The filesystem read primitive was validated with equivalent Node HTTP handling for the affected code path, including that Node preserves /../secret.txt in request.url and that bare server.listen(port) binds to all interfaces on this platform.

PoC

1. Create a custom UI directory at /tmp/logto-ui/static with /tmp/logto-ui/static/index.html. 2. Create a sibling file outside the static root, for example /tmp/logto-ui/secret.txt. 3. Start the tunnel with logto-tunnel --endpoint https:// .logto.app --port 9000 --experience-path /tmp/logto-ui/static. 4. Request http:// :9000/../secret.txt. 5. The response body contains the contents of /tmp/logto-ui/secret.txt.

Impact

The observed result is arbitrary file read outside the configured custom UI static directory. If the tunnel port is reachable from another host, an unauthenticated network peer can read local files readable by the logto-tunnel process, including development secrets or credentials stored near the custom UI project.

Affected package ranges reported by GitHub: @logto/tunnel: <= 0.3.8

Scores and how they were measured

CVSS base severity

8.7

Version 4.0As of

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N

Measurement source (opens a new tab)

How bad it is if exploited. Not a prediction of exploitation or proof you are exposed.

EPSS probability

0.5%

Scored Percentile 45.6%

Model and measurement source (opens a new tab)

A model's estimate of exploitation in the next 30 days, not certainty or your own risk.

Related technology

Sources

  1. Primary source

    GitHub-reviewed advisory GHSA-rxjr-6c9q-h67x (opens a new tab)

    The public advisory supplies the description, affected package/version ranges, and any listed CVSS metric. GitHub review is not local review.

    Published Checked

  2. Primary source

    GitHub public advisory API page (opens a new tab)

    The API page supplied GHSA-rxjr-6c9q-h67x, its actual identifiers, source dates, and structured metrics.

    Published Date not suppliedChecked

  3. Primary source

    FIRST measured EPSS score (opens a new tab)

    Measured EPSS probability and percentile for CVE-2026-63188, scored 2026-11-05. This is a model estimate, not proof of exposure.

    Published Checked

Cite this record

For factual claims, cite the primary sources above; cite KEVWire for its compilation, dates, and classifications.

APA

KEVWire. (2026, November 5). logto-tunnel serves files outside `--experience-path` via path traversal (CVE-2026-63188). https://kevwire.com/record/CVE-2026-63188

MLA

"logto-tunnel serves files outside `--experience-path` via path traversal (CVE-2026-63188)." KEVWire, 5 Nov. 2026, kevwire.com/record/CVE-2026-63188.

Chicago

KEVWire. "logto-tunnel serves files outside `--experience-path` via path traversal (CVE-2026-63188)." Last modified November 5, 2026. https://kevwire.com/record/CVE-2026-63188.

Evidence summary (plain text)

logto-tunnel serves files outside `--experience-path` via path traversal (Aug 19, 2026).
@logto/tunnel serves custom sign-in experience files from the --experience-path directory. When the tunnel service is reachable, a requester can use ../ path segments in a static asset request to read files outside that directory that the CLI process can read.

The tunnel command accepts --experience-path as the local folder path for custom sign-in experience assets. packages/tunnel/src/commands/tunnel/index.ts enables createStaticFileProxy(path) when that option is set and sends non-Logto, non---experience-uri requests to that static proxy. The server is started with server.listen(port).
CVSS 8.7 (version 4.0; evidence as of Nov 5, 2026; https://github.com/advisories/GHSA-rxjr-6c9q-h67x).
EPSS 0.5% for the following 30 days, scored Nov 5, 2026 (https://api.first.org/data/v1/epss?cve=CVE-2026-63188&date=2026-11-05).
Sources:
GitHub-reviewed advisory GHSA-rxjr-6c9q-h67x: https://github.com/advisories/GHSA-rxjr-6c9q-h67x
GitHub public advisory API page: https://api.github.com/advisories?type=reviewed&per_page=100&sort=updated&direction=desc
FIRST measured EPSS score: https://api.first.org/data/v1/epss?cve=CVE-2026-63188&date=2026-11-05
Record ID: CVE-2026-63188.
Record origin: Ingested record.
AI evidence: Not assessed.
Known exploitation: Not assessed.
Zero-day status: Not assessed. KEV membership alone does not establish zero-day status.
About this data

This record was ingested from a data source. Retrieved: Nov 5, 2026, 19:11 UTC. Ingestion is not an independent editorial investigation.

A CISA KEV listing documents known exploitation, not necessarily a zero-day; absence from the catalog does not prove a vulnerability has never been exploited.

Technology tags indicate possible relevance, not verified exposure. Confirm the affected product, version, and configuration against your own inventory; KEVWire does not scan your systems.

A personal reading checklist on this device, not verified remediation.

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