# GHSA-2phg-qgmm-r638: Sliver has Potential Zip Bomb Denial of Service in GzipEncoder

> Unauthenticated remote attackers can crash the Sliver C2 server by sending highly compressed gzip data, exhausting memory and CPU resources.

- **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:** 25 Feb 2026
- **Also known as:** GO-2026-4548

## What is GHSA-2phg-qgmm-r638?

GHSA-2phg-qgmm-r638 is a denial of service vulnerability in github.com/bishopfox/sliver, published on 25 Feb 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

### Summary

GzipEncoder does not limit output size when processing compressed data. This allows unauthenticated remote attackers to crash sliver server by sending a http request with highly compressed gzip data (aka zip bomb).

### Details

In `util/encoders/gzip.go`, `Decode()` method decompresses given data by reading the entire gzip buffer at once without limiting output size.

### PoC

```python
data = gzip.compress(bytes(1024 * 1024 * 1024)) * 16
requests.post(f"http://172.17.0.2/{nonce}", data=data)
```

### Impact

Unauthenticated remote attackers can exhaust memory and cpu resource of sliver server and crash it when they have GzipEncoderID, which can be easily retrived from implant's http traffic, or by brute-forcing.

A fixed version is available at https://github.com/BishopFox/sliver/releases/tag/v1.7.2.

## Which versions are affected by GHSA-2phg-qgmm-r638?

3 open source packages ship an affected version, including github.com/bishopfox/sliver.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `github.com/bishopfox/sliver` | Go | All versions | 1.7.2 |
| `github.com/bishopfox/sliver` | Go | All versions | 1.7.2 |
| `github.com/bishopfox/sliver` | Go | All versions | 1.7.2 |

## How do I fix GHSA-2phg-qgmm-r638?

Upgrade github.com/bishopfox/sliver to 1.7.2 or later.

## Is GHSA-2phg-qgmm-r638 being exploited?

There is no known exploitation of GHSA-2phg-qgmm-r638 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for GHSA-2phg-qgmm-r638 and fix it if it is affected.

What it is: GHSA-2phg-qgmm-r638 is a denial of service vulnerability in github.com/bishopfox/sliver, published on 25 Feb 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-2phg-qgmm-r638 in the wild and no public exploit code.

Affected packages and fixed versions:
- github.com/bishopfox/sliver (Go): affected all versions; fixed in 1.7.2
- github.com/bishopfox/sliver (Go): affected all versions; fixed in 1.7.2
- github.com/bishopfox/sliver (Go): affected all versions; fixed in 1.7.2

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-2phg-qgmm-r638/ (Markdown: https://insights.sbomify.com/GHSA-2phg-qgmm-r638/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/GHSA-2phg-qgmm-r638

---
From sbomify Insights: https://insights.sbomify.com/GHSA-2phg-qgmm-r638/
Summaries are generated and may contain mistakes; the official description above is the record.