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
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.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
Remediation advice
Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.
Frequently Asked Questions
- What is GHSA-2PHG-QGMM-R638? GHSA-2PHG-QGMM-R638 is a high-severity security vulnerability in github.com/BishopFox/sliver (go), affecting versions < 1.7.2. It is fixed in 1.7.2.
- Which versions of github.com/BishopFox/sliver are affected by GHSA-2PHG-QGMM-R638? github.com/BishopFox/sliver (go) versions < 1.7.2 is affected.
- Is there a fix for GHSA-2PHG-QGMM-R638? Yes. GHSA-2PHG-QGMM-R638 is fixed in 1.7.2. Upgrade to this version or later.
- Is GHSA-2PHG-QGMM-R638 exploitable, and should I be worried? Whether GHSA-2PHG-QGMM-R638 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether GHSA-2PHG-QGMM-R638 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix GHSA-2PHG-QGMM-R638? Upgrade
github.com/BishopFox/sliverto 1.7.2 or later.