# CVE-2018-0277: Denial of service in Cisco Identity Services Engine > An unauthenticated remote attacker can cause a denial of service on Cisco ISE by sending a crafted EAP-TLS certificate, triggering an unexpected application server restart. - **Severity:** High 8.6 (`CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/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:** 17 May 2018 - **Updated:** 29 Nov 2024 - **Also known as:** GHSA-7hf4-2cmf-xpcc ## What is CVE-2018-0277? CVE-2018-0277 is a high-severity denial of service vulnerability in Cisco Identity Services Engine, published on 17 May 2018. An attacker can exploit it over the internet without logging in, with no action from the victim. ### Official description A vulnerability in the Extensible Authentication Protocol-Transport Layer Security (EAP-TLS) certificate validation during EAP authentication for the Cisco Identity Services Engine (ISE) could allow an unauthenticated, remote attacker to cause the ISE application server to restart unexpectedly, causing a denial of service (DoS) condition on an affected system. The vulnerability is due to incomplete input validation of the client EAP-TLS certificate. An attacker could exploit this vulnerability by initiating EAP authentication over TLS to the ISE with a crafted EAP-TLS certificate. A successful exploit could allow the attacker to restart the ISE application server, resulting in a DoS condition on the affected system. The ISE application could continue to restart while the client attempts to establish the EAP authentication connection. If an attacker attempted to import the same EAP-TLS certificate to the ISE trust store, it could trigger a DoS condition on the affected system. This exploit vector would require the attacker to have valid administrator credentials. The vulnerability affects Cisco ISE, Cisco ISE Express, and Cisco ISE Virtual Appliance. Cisco Bug IDs: CSCve31857. Weakness: CWE-295 (Improper Certificate Validation) ## Which versions are affected by CVE-2018-0277? It affects 1 product. Products: Cisco Identity Services Engine. ## How do I fix CVE-2018-0277? No fix has been published for CVE-2018-0277 yet. Limit exposure of the affected software until one is available. ## Is CVE-2018-0277 being exploited? There is no known exploitation of CVE-2018-0277 in the wild and no public exploit code. ## Other vulnerabilities in Cisco Identity Services Engine - [CVE-2026-76460](https://insights.sbomify.com/CVE-2026-76460/): Cisco Identity Services Engine Incorrect Use of Privileged APIs (critical 10.0, exploited in the wild) - [CVE-2025-20337](https://insights.sbomify.com/CVE-2025-20337/): Cisco Identity Services Engine Injection (critical 10.0, exploited in the wild) - [CVE-2025-20281](https://insights.sbomify.com/CVE-2025-20281/): Cisco Identity Services Engine Injection (critical 10.0, exploited in the wild) - [CVE-2026-20130](https://insights.sbomify.com/CVE-2026-20130/): Cisco Identity Services Engine Hardening Release - Improper Neutralization Vulnerabilities (critical 10.0) - [CVE-2026-20192](https://insights.sbomify.com/CVE-2026-20192/): Cisco Identity Services Engine Hardening Release - Access Control Vulnerabilities (critical 10.0) ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2018-0277 and fix it if it is affected. What it is: CVE-2018-0277 is a high-severity denial of service vulnerability in Cisco Identity Services Engine, published on 17 May 2018. 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-2018-0277 in the wild and no public exploit code. Affected product: Cisco Identity Services Engine. 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-2018-0277/ (Markdown: https://insights.sbomify.com/CVE-2018-0277/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2018-0277 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2018-0277 - OSV: https://osv.dev/vulnerability/CVE-2018-0277 --- From sbomify Insights: https://insights.sbomify.com/CVE-2018-0277/ Summaries are generated and may contain mistakes; the official description above is the record.