TUF Luck: Escaping the Sandbox in go-tuf via TAP 4 Map Files
Vulnerability ID: CVE-2026-24686
CVSS Score: 9.8
Published: 2026-01-26
A critical Path Traversal vulnerability in the go-tuf TAP 4 Multirepo client allows attackers to overwrite arbitrary files via malicious repository names in the map file.
TL;DR
The go-tuf library, widely used for secure software updates, contained a path traversal flaw in its TAP 4 support. By crafting a malicious map file with traversal sequences in repository names (e.g., "../../etc/cron.d"), an attacker can force the client to write metadata files to arbitrary locations on the host system. This turns a routine update check into an Arbitrary File Write primitive, potentially leading to RCE.
⚠️ Exploit Status: POC
Technical Details
- CWE ID: CWE-22 (Path Traversal)
- Attack Vector: Network / Local (Configuration)
- CVSS v3.1 (Est): 9.8 (Critical)
- Impact: Arbitrary File Write / RCE
- Affected Component: metadata/multirepo/multirepo.go
- Status: Patched
Affected Systems
- Go applications using the-update-framework/go-tuf
- Systems utilizing TAP 4 Multirepo configurations
- Supply chain security tools built on go-tuf
-
theupdateframework/go-tuf: < Commit d361e2ea (Fixed in:
Commit d361e2ea)
Code Analysis
Commit: d361e2e
Fix path traversal in TAP 4 repo names via regex validation
+ if !validRepoNamePattern.MatchString(name) {
+ return fmt.Errorf("%w: %q must start with alphanumeric...", ErrInvalidRepoName, name)
+ }
Commit: bde5f18
Refactor Key.ID() to prevent panics (Pre-cursor work)
Exploit Details
- Internal Research: The fix commit implicitly demonstrates the exploit vector via the added test cases and validation logic.
Mitigation Strategies
- Input Validation: Enforce strict alphanumeric naming conventions for repositories.
- Principle of Least Privilege: Run update clients with minimal filesystem permissions.
- Sandboxing: Use filesystem namespaces or containers to limit write access.
Remediation Steps:
- Update
go-tufto the latest version containing commitd361e2ea24e427581343dee5c7a32b485d79fcc0. - Audit existing TAP 4 map files for traversal sequences.
- Rebuild any applications dependent on the vulnerable library.
References
Read the full report for CVE-2026-24686 on our website for more details including interactive diagrams and full exploit analysis.
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