# CVE-2017-12236: Auth bypass in Cisco IOS XE

> An unauthenticated remote attacker can bypass authentication to inject invalid EID-to-RLOC mappings in Cisco IOS XE LISP map servers.

- **Severity:** Critical 9.8 (`CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 28 Sep 2017
- **Updated:** 5 Aug 2024
- **Also known as:** GHSA-c79j-mjvv-wx7f

## What is CVE-2017-12236?

CVE-2017-12236 is a critical authentication bypass vulnerability in Cisco Ios Xe, published on 28 Sep 2017. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A vulnerability in the implementation of the Locator/ID Separation Protocol (LISP) in Cisco IOS XE 3.2 through 16.5 could allow an unauthenticated, remote attacker using an x tunnel router to bypass authentication checks performed when registering an Endpoint Identifier (EID) to a Routing Locator (RLOC) in the map server/map resolver (MS/MR). The vulnerability is due to a logic error introduced via a code regression for the affected software. An attacker could exploit this vulnerability by sending specific valid map-registration requests, which will be accepted by the MS/MR even if the authentication keys do not match, to the affected software. A successful exploit could allow the attacker to inject invalid mappings of EIDs to RLOCs in the MS/MR of the affected software. This vulnerability affects Cisco devices that are configured with LISP acting as an IPv4 or IPv6 map server. This vulnerability affects Cisco IOS XE Software release trains 3.9E and Everest 16.4. Cisco Bug IDs: CSCvc18008.

Weakness: CWE-287 (Improper Authentication)

## Which versions are affected by CVE-2017-12236?

It affects 1 product.


Products: Cisco Ios Xe.

## How do I fix CVE-2017-12236?

No fix has been published for CVE-2017-12236 yet. Limit exposure of the affected software until one is available.

## Is CVE-2017-12236 being exploited?

There is no known exploitation of CVE-2017-12236 in the wild and no public exploit code.

## Other vulnerabilities in Cisco Ios Xe

- [CVE-2023-20198](https://insights.sbomify.com/CVE-2023-20198/): Cisco IOS XE Web UI Privilege Escalation (critical 10.0, exploited in the wild)
- [CVE-2018-0151](https://insights.sbomify.com/CVE-2018-0151/): Cisco IOS Software and Cisco IOS XE Software Quality of Service Remote Code Execution (critical 9.8, exploited in the wild)
- [CVE-2023-20273](https://insights.sbomify.com/CVE-2023-20273/): Cisco IOS XE Web UI Command Injection (high 7.2, exploited in the wild)
- [CVE-2025-20188](https://insights.sbomify.com/CVE-2025-20188/): Hardcoded credentials in Cisco IOS XE Software (critical 10.0)
- [CVE-2021-34770](https://insights.sbomify.com/CVE-2021-34770/): Cisco IOS XE Software for Catalyst 9000 Family Wireless Controllers CAPWAP Remote Code Execution Vulnerability (critical 10.0)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2017-12236 and fix it if it is affected.

What it is: CVE-2017-12236 is a critical authentication bypass vulnerability in Cisco Ios Xe, published on 28 Sep 2017. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2017-12236 in the wild and no public exploit code.

Affected product: Cisco Ios Xe. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2017-12236/ (Markdown: https://insights.sbomify.com/CVE-2017-12236/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2017-12236
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2017-12236
- OSV: https://osv.dev/vulnerability/CVE-2017-12236

---
From sbomify Insights: https://insights.sbomify.com/CVE-2017-12236/
Summaries are generated and may contain mistakes; the official description above is the record.