# CVE-2023-41378: Calico Typha hangs during unclean TLS handshake

> An attacker can cause a denial of service in Calico Typha by initiating an unclean TLS handshake that blocks the server's main loop indefinitely.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/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:** Yes
- **Published:** 6 Nov 2023
- **Updated:** 5 Sep 2024
- **Also known as:** GHSA-5r5h-q934-cccp

## What is CVE-2023-41378?

CVE-2023-41378 is a high-severity denial of service vulnerability in Calico Typha, published on 6 Nov 2023. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

In certain conditions for Calico Typha (v3.26.2, v3.25.1 and below), and Calico Enterprise Typha (v3.17.1, v3.16.3, v3.15.3 and below), a client TLS handshake can block the Calico Typha server indefinitely, resulting in denial of service. The TLS Handshake() call is performed inside the main server handle for loop without any timeout allowing an unclean TLS handshake to block the main loop indefinitely while other connections will be idle waiting for that handshake to finish.

Weakness: CWE-755 (Improper Handling of Exceptional Conditions), CWE-703 (Improper Check or Handling of Exceptional Conditions), CWE-400 (Uncontrolled Resource Consumption)

## Which versions are affected by CVE-2023-41378?

4 open source packages ship an affected version, including github.com/projectcalico/calico. It affects 3 products.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `github.com/projectcalico/calico` | Go | All versions to 3.25.1 | None |
| `github.com/projectcalico/calico` | Go | All versions to 3.25.1 | None |
| `github.com/projectcalico/calico` | Go | From 3.26.0 | 3.26.3 |
| `github.com/projectcalico/calico` | Go | From 3.26.0 | 3.26.3 |

Products: Tigera Calico Cloud, Tigera Calico Enterprise, Tigera Calico Os.

## How do I fix CVE-2023-41378?

Upgrade github.com/projectcalico/calico to 3.26.3 or later.

## Is CVE-2023-41378 being exploited?

There is no known exploitation of CVE-2023-41378 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-41378 and fix it if it is affected.

What it is: CVE-2023-41378 is a high-severity denial of service vulnerability in Calico Typha, published on 6 Nov 2023. 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-2023-41378 in the wild and no public exploit code.

Affected packages and fixed versions:
- github.com/projectcalico/calico (Go): affected all versions up to 3.25.1; no fix listed
- github.com/projectcalico/calico (Go): affected all versions up to 3.25.1; no fix listed
- github.com/projectcalico/calico (Go): affected from 3.26.0; fixed in 3.26.3
- github.com/projectcalico/calico (Go): affected from 3.26.0; fixed in 3.26.3

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-2023-41378/ (Markdown: https://insights.sbomify.com/CVE-2023-41378/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-41378
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-41378
- OSV: https://osv.dev/vulnerability/CVE-2023-41378

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-41378/
Summaries are generated and may contain mistakes; the official description above is the record.