GHSA-HJR9-WJ7V-7HV8

A specially crafted nonce routes unauthenticated requests through the NoEncoder path, where startSessionHandler() reads the entire request body without limits, allowing attacker-driven memory exhaustion and process crash.

Details

• server/encoders/encoders.go: EncoderFromNonce() returns NoEncoder when nonce % 65537 == 0 (lines 254-264); NoEncoder is a passthrough (util/encoders/nop.go:22-32).
• server/c2/http.go: anonymousHandler() routes requests with any encoder (including NoEncoder) to startSessionHandler() (lines 551-562).
• server/c2/http.go: startSessionHandler() uses io.ReadAll(req.Body) without a size cap (lines 564-643), unlike the authenticated path that uses io.LimitedReader (readReqBody(), lines 708-732).

PoC

An attacker could send an HTTP POST with a nonce that is a multiple of 65537 (e.g., ?q=65537) so it is handled by startSessionHandler() with a NoEncoder, and advertise a very large Content-Length while streaming data. Because this handler uses io.ReadAll(req.Body) without a size limit, the server is expected to allocate large amounts of memory and may exhaust available RAM, leading to process termination on typical deployments.

Unauthenticated remote DoS: attacker can crash the Sliver HTTP listener, dropping all active sessions and locking out operators until restart. No credentials or non-default config required.

The application allocates resources such as memory, threads, or file descriptors based on untrusted input without enforcing a cap. Typical impact: resource exhaustion leading to denial of service.

Kodem intelligence

1. What is GHSA-HJR9-WJ7V-7HV8? GHSA-HJR9-WJ7V-7HV8 is a medium-severity allocation of resources without limits or throttling vulnerability in github.com/bishopfox/sliver (go), affecting versions >= 1.5.0, <= 1.5.44. No fixed version is listed yet. The application allocates resources such as memory, threads, or file descriptors based on untrusted input without enforcing a cap.
2. Which versions of github.com/bishopfox/sliver are affected by GHSA-HJR9-WJ7V-7HV8? github.com/bishopfox/sliver (go) versions >= 1.5.0, <= 1.5.44 is affected.
3. Is there a fix for GHSA-HJR9-WJ7V-7HV8? No fixed version is listed for GHSA-HJR9-WJ7V-7HV8 yet. Monitor the advisory for updates and apply mitigations in the interim.
4. Is GHSA-HJR9-WJ7V-7HV8 exploitable, and should I be worried? Whether GHSA-HJR9-WJ7V-7HV8 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
5. What actually determines whether GHSA-HJR9-WJ7V-7HV8 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.
6. How do I fix GHSA-HJR9-WJ7V-7HV8? No fixed version is listed yet. In the interim: Apply per-request resource limits and enforce them before allocation. Rate-limit callers at the network or application layer.