# GHSA-22w5-2fxg-vrwx: Impact Unauthenticated denial of service. > OpenTofu suffers from high CPU usage and potential denial of service when connecting to untrusted or compromised servers due to inefficient parsing in underlying Go libraries. - **Severity:** Not scored - **Exploited in the wild:** Not known - **Login needed:** Not needed - **Attackable:** Over the internet - **Victim action needed:** Not needed - **Fix available:** Yes - **Published:** 20 Aug 2026 - **Also known as:** GO-2026-6262 ## What is GHSA-22w5-2fxg-vrwx? GHSA-22w5-2fxg-vrwx is a denial of service vulnerability in github.com/opentofu/opentofu, published on 20 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim. ### Official description ### Impact Unauthenticated denial of service. ### Summary When OpenTofu performs requests against an untrusted (or compromised) third-party server or connects to an attacker-controlled server, the initial connection negotiation can produce high CPU usage, leading to possible denial of service. These vulnerabilities **do not** permit arbitrary code execution or allow disclosure of confidential information. ### Details OpenTofu relies on third-party implementations of TLS certificate verification and HTTP request execution from the standard library of the Go programming language. The Go project has recently published the following advisories for those implementations which indirectly affect OpenTofu's behavior: - [CVE-2026-42504](https://www.cve.org/CVERecord?id=CVE-2026-42504): Quadratic complexity in WordDecoder.DecodeHeader in mime - [CVE-2026-27145](https://www.cve.org/CVERecord?id=CVE-2026-27145): Inefficient candidate hostname parsing in crypto/x509 CVE-2026-42504 affects OpenTofu's K8S remote state implementation. The operator of a configuration that uses such a backend needs to double-check the trustworthiness of the server used for this purpose. In situations where the server is untrusted or compromised, an attacker could configure it to respond with an intentionally crafted HTTP response designed to target this specific vulnerability in the Go standard library, potentially leading to high CPU usage. CVE-2026-27145 has a similar outcome: if an untrusted or compromised third-party server is used, an attacker could craft a specific TLS certificate that targets this vulnerability in the Go standard library, which could also lead to high CPU usage. Typical use of OpenTofu already requires caution in selection of third-party dependencies. ### Patches OpenTofu v1.11.9 and v1.12.2 address these vulnerabilities by upgrading to the Go versions that fix them (v1.25.11 and v1.26.3). The OpenTofu v1.10 series is also impacted by these vulnerabilities. However, that series is built with a version of Go for which no upstream fix is available. Adopting Go 1.25.11 for that series would effectively end support for certain versions of macOS and Linux, and the OpenTofu Project has determined that the impact of these vulnerabilities is not high enough to justify that disruption in a patch release. For those using OpenTofu v1.10 releases, we recommend planning an upgrade to OpenTofu v1.11.9 in the near future. ## Which versions are affected by GHSA-22w5-2fxg-vrwx? 5 open source packages ship an affected version, including github.com/opentofu/opentofu. | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `github.com/opentofu/opentofu` | Go | All versions | 1.11.9, 1.12.2 | | `github.com/opentofu/opentofu` | Go | All versions | 1.11.9 | | `github.com/opentofu/opentofu` | Go | All versions | 1.11.9 | | `github.com/opentofu/opentofu` | Go | From 1.12.0-beta1 | 1.12.2 | | `github.com/opentofu/opentofu` | Go | From 1.12.0-beta1 | 1.12.2 | ## How do I fix GHSA-22w5-2fxg-vrwx? Upgrade github.com/opentofu/opentofu to a fixed version for your release line: 1.11.9 or 1.12.2. ## Is GHSA-22w5-2fxg-vrwx being exploited? There is no known exploitation of GHSA-22w5-2fxg-vrwx in the wild and no public exploit code. ## Fix prompt for AI coding agents ```text Check this codebase for GHSA-22w5-2fxg-vrwx and fix it if it is affected. What it is: GHSA-22w5-2fxg-vrwx is a denial of service vulnerability in github.com/opentofu/opentofu, published on 20 Aug 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 GHSA-22w5-2fxg-vrwx in the wild and no public exploit code. Affected packages and fixed versions: - github.com/opentofu/opentofu (Go): affected all versions; fixed in 1.11.9, 1.12.2 - github.com/opentofu/opentofu (Go): affected all versions; fixed in 1.11.9 - github.com/opentofu/opentofu (Go): affected all versions; fixed in 1.11.9 - github.com/opentofu/opentofu (Go): affected from 1.12.0-beta1; fixed in 1.12.2 - github.com/opentofu/opentofu (Go): affected from 1.12.0-beta1; fixed in 1.12.2 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/GHSA-22w5-2fxg-vrwx/ (Markdown: https://insights.sbomify.com/GHSA-22w5-2fxg-vrwx/index.md) ``` ## Sources - OSV: https://osv.dev/vulnerability/GHSA-22w5-2fxg-vrwx --- From sbomify Insights: https://insights.sbomify.com/GHSA-22w5-2fxg-vrwx/ Summaries are generated and may contain mistakes; the official description above is the record.