# CVE-2023-34758: Silver vulnerable to MitM attack against implants due to a cryptography vulnerability

> Attackers can perform man-in-the-middle attacks against Sliver C2 framework due to improper cryptographic implementation.

- **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:** 28 Aug 2023
- **Updated:** 2 Oct 2024
- **Also known as:** GHSA-8jxm-xp43-qh3q

## What is CVE-2023-34758?

CVE-2023-34758 is a high-severity vulnerability in n/a, published on 28 Aug 2023. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Sliver from v1.5.x to v1.5.39 has an improper cryptographic implementation, which allows attackers to execute a man-in-the-middle attack via intercepted and crafted responses.

Weakness: CWE-327 (Use of a Broken or Risky Cryptographic Algorithm)

## Which versions are affected by CVE-2023-34758?

2 open source packages ship an affected version, including github.com/bishopfox/sliver. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `github.com/bishopfox/sliver` | Go | From 1.5.0 | 1.5.40 |
| `github.com/bishopfox/sliver` | Go | From 1.5.0 | 1.5.40 |

Products: Bishopfox Sliver.

## How do I fix CVE-2023-34758?

Upgrade github.com/bishopfox/sliver to 1.5.40 or later.

## Is CVE-2023-34758 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2023-34758 exists.

## Other vulnerabilities in n/a

- [CVE-2026-25791](https://insights.sbomify.com/CVE-2026-25791/): Sliver has a DNS C2 OTP Bypass Allows Unauthenticated Session Flooding and Denial of Service (high 7.5)
- [CVE-2025-27090](https://insights.sbomify.com/CVE-2025-27090/): Server-Side Request Forgery (SSRF) in sliver teamserver (medium 6.9)
- [CVE-2026-25760](https://insights.sbomify.com/CVE-2026-25760/): Website Path Traversal / Arbitrary File Read (Authenticated) in Sliver (medium 6.5)
- [CVE-2026-34227](https://insights.sbomify.com/CVE-2026-34227/): Sliver One-Click Remote Access: Insecure CORS & Unauthenticated MCP Interface (medium 5.9)
- [CVE-2026-32941](https://insights.sbomify.com/CVE-2026-32941/): Sliver Vulnerable to Authenticated OOM via Memory Exhaustion in mTLS/WireGuard Transports (medium 5.7)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-34758 and fix it if it is affected.

What it is: CVE-2023-34758 is a high-severity vulnerability in n/a, published on 28 Aug 2023. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2023-34758 exists.

Affected packages and fixed versions:
- github.com/bishopfox/sliver (Go): affected from 1.5.0; fixed in 1.5.40
- github.com/bishopfox/sliver (Go): affected from 1.5.0; fixed in 1.5.40

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-2023-34758/ (Markdown: https://insights.sbomify.com/CVE-2023-34758/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-34758
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-34758
- OSV: https://osv.dev/vulnerability/CVE-2023-34758

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-34758/
Summaries are generated and may contain mistakes; the official description above is the record.