# CVE-2015-1855: Security feature bypass in Ruby

> Remote attackers can spoof servers by bypassing hostname validation in the Ruby OpenSSL extension due to improper wildcard and character handling.

- **Severity:** Medium 5.9 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 29 Nov 2019
- **Updated:** 6 Aug 2024
- **Also known as:** DLA-224-1, DSA-3245-1, DSA-3246-1, DSA-3247-1, GHSA-4x8v-74xf-h4g3, MGASA-2015-0178, UBUNTU-CVE-2015-1855

## What is CVE-2015-1855?

CVE-2015-1855 is a medium-severity vulnerability in Debian Debian Linux, published on 29 Nov 2019. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

verify_certificate_identity in the OpenSSL extension in Ruby before 2.0.0 patchlevel 645, 2.1.x before 2.1.6, and 2.2.x before 2.2.2 does not properly validate hostnames, which allows remote attackers to spoof servers via vectors related to (1) multiple wildcards, (1) wildcards in IDNA names, (3) case sensitivity, and (4) non-ASCII characters.

Weakness: CWE-20 (Improper Input Validation)

## Which versions are affected by CVE-2015-1855?

It affects 5 products.


Products: Debian Debian Linux, Puppet Puppet Agent, Puppet Puppet Enterprise, Ruby-Lang Ruby, Ruby-Lang Trunk.

## How do I fix CVE-2015-1855?

Upgrade to a fixed version.

## Is CVE-2015-1855 being exploited?

There is no known exploitation of CVE-2015-1855 in the wild and no public exploit code.

Public exploit code:

- poc for CVE-2015-1855 (github_poc): https://github.com/vpereira/CVE-2015-1855

## Other vulnerabilities in Debian Debian Linux

- [CVE-2015-3306](https://insights.sbomify.com/CVE-2015-3306/): ProFTPD Improper Access Control (critical 10.0, exploited in the wild)
- [CVE-2025-49113](https://insights.sbomify.com/CVE-2025-49113/): RoundCube Webmail Deserialization of Untrusted Data (critical 9.9, exploited in the wild)
- [CVE-2026-24061](https://insights.sbomify.com/CVE-2026-24061/): GNU InetUtils Argument Injection (critical 9.8, exploited in the wild)
- [CVE-2025-39682](https://insights.sbomify.com/CVE-2025-39682/): Linux Kernel Improper Check for Unusual or Exceptional Conditions (critical 9.8, exploited in the wild)
- [CVE-2024-9680](https://insights.sbomify.com/CVE-2024-9680/): Mozilla Firefox Use-After-Free (critical 9.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2015-1855 and fix it if it is affected.

What it is: CVE-2015-1855 is a medium-severity vulnerability in Debian Debian Linux, published on 29 Nov 2019. 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-2015-1855 in the wild and no public exploit code.

Affected product: Debian Debian Linux. 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-2015-1855/ (Markdown: https://insights.sbomify.com/CVE-2015-1855/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2015-1855
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2015-1855
- OSV: https://osv.dev/vulnerability/CVE-2015-1855

---
From sbomify Insights: https://insights.sbomify.com/CVE-2015-1855/
Summaries are generated and may contain mistakes; the official description above is the record.