# CVE-2026-46727: Use after free in Ruby

> A race condition in Ruby's DNS timeout handler causes a use-after-free, allowing remote attackers to crash processes or potentially execute code via malicious DNS responses.

- **Severity:** High 8.1 (`CVSS:3.1/AV:N/AC:H/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:** Yes
- **Published:** 22 May 2026
- **Updated:** 22 May 2026
- **Also known as:** BIT-ruby-2026-46727, BIT-ruby-min-2026-46727, GHSA-jfc8-2xw7-c79m, MINI-hw54-f695-m9w5, UBUNTU-CVE-2026-46727, openSUSE-SU-2026:10839-1

## What is CVE-2026-46727?

CVE-2026-46727 is a high-severity use after free vulnerability in Ruby-Lang Ruby, published on 22 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

An issue was discovered in Ruby 4 before 4.0.5. A race condition leading to a use-after-free in the pthread-based getaddrinfo timeout handler (rb_getaddrinfo in ext/socket/raddrinfo.c) allows a remote attacker who can delay DNS responses near the user-specified timeout to crash a Ruby process that calls Addrinfo.getaddrinfo(..., timeout:) or Socket.tcp(..., resolv_timeout:). Memory-corruption-based exploitation is theoretically possible. The attack could, for example, be carried out through a crafted authoritative DNS server or recursive resolver.

Weakness: CWE-362 (Concurrent Execution using Shared Resource with Improper Synchronization)

## Which versions are affected by CVE-2026-46727?

2 open source packages ship an affected version, including ruby and ruby-min. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `ruby` | Bitnami | From 4.0.0 | 4.0.5 |
| `ruby-min` | Bitnami | From 4.0.0 | 4.0.5 |
| `ruby4.0` | openSUSE:Tumbleweed | All versions | 4.0.5-1.1 |

Products: Ruby-Lang Ruby.

## How do I fix CVE-2026-46727?

Upgrade ruby to 4.0.5 or later.

## Is CVE-2026-46727 being exploited?

There is no known exploitation of CVE-2026-46727 in the wild and no public exploit code.

## Other vulnerabilities in Ruby-Lang Ruby

- [CVE-2009-4124](https://insights.sbomify.com/CVE-2009-4124/): Memory corruption in n/a (critical 10.0)
- [CVE-2022-28738](https://insights.sbomify.com/CVE-2022-28738/): Use after free in n/a (critical 9.8)
- [CVE-2011-4121](https://insights.sbomify.com/CVE-2011-4121/): Weak cryptography in OpenSSL extension of Ruby (Git trunk) (critical 9.8)
- [CVE-2017-17790](https://insights.sbomify.com/CVE-2017-17790/): Command injection in n/a (critical 9.8)
- [CVE-2017-11465](https://insights.sbomify.com/CVE-2017-11465/): Memory corruption in n/a (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-46727 and fix it if it is affected.

What it is: CVE-2026-46727 is a high-severity use after free vulnerability in Ruby-Lang Ruby, published on 22 May 2026. 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-2026-46727 in the wild and no public exploit code.

Affected packages and fixed versions:
- ruby (Bitnami): affected from 4.0.0; fixed in 4.0.5
- ruby-min (Bitnami): affected from 4.0.0; fixed in 4.0.5

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-2026-46727/ (Markdown: https://insights.sbomify.com/CVE-2026-46727/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-46727
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-46727
- OSV: https://osv.dev/vulnerability/CVE-2026-46727

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-46727/
Summaries are generated and may contain mistakes; the official description above is the record.