GHSA-jqc5-w2xx-5vq4 is a medium-severity (CVSS 4.7) Path Traversal vulnerability in github.com/theupdateframework/go-tuf/v2. A fix is available for github.com/theupdateframework/go-tuf/v2 — see the affected versions and patch details below.
go-tuf Path Traversal in TAP 4 Multirepo Client Allows Arbitrary File Write via Malicious Repository Names
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
Exploitation and automatability from CISA’s SSVC triage for GHSA-jqc5-w2xx-5vq4.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
GHSA-jqc5-w2xx-5vq4 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 377,238 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
github.com/theupdateframework/go-tuf/v2Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.
Description
Security Vulnerability: Path Traversal in TAP 4 Multirepo Client
Summary
go-tuf's TAP 4 Multirepo Client uses the map file repository name string (repoName) as a filesystem path component when selecting the local metadata cache directory. If an application accepts a map file from an untrusted source, an attacker can supply a repoName containing traversal (e.g., ../escaped-repo) and cause go-tuf to create directories and write the root metadata file outside the intended LocalMetadataDir cache base, within the running process's filesystem permissions.
Affected Component
| Field | Value |
|---|---|
| File | metadata/multirepo/multirepo.go |
| Function | (*MultiRepoClient) initTUFClients() error |
| Callsite | metadataDir := filepath.Join(client.Config.LocalMetadataDir, repoName) (around line 129 at the pinned commit) |
Impact
When the TAP 4 map file content is attacker-controlled, this enables arbitrary file write relative to the process permissions (via metadata persistence during client initialization). This can be used to overwrite files writable by the process (for example, configuration files in writable directories) and may enable further compromise depending on the deployment environment.
Note: Exploitability is deployment-dependent. If the map file is always local and trusted (not attacker-controlled), this reduces to a misconfiguration risk rather than a remotely triggerable issue.
Attacker Model
- Attacker can cause the application to load a TAP 4 map file whose
repositorieskeys are attacker-controlled (for example: fetched from a URL, supply-chain substituted, or otherwise attacker-influenced input). - Local caching is enabled (
DisableLocalCache=false) and the configuredLocalMetadataDiris writable by the running process.
Claim Ceiling: HIGH when the map file is attacker-controlled; if the map file is always local and trusted, this is closer to a configuration footgun and likely lands as MEDIUM/LOW.
| Field | Value |
|---|---|
| Affected Versions | ≤ 2.4.0 |
| Verified On | Commit bde5f18dc95dfac365fc452ee4e278e5fd66d4b4 (tag v2.4.0) |
Note: First affected version has not been bisected.
Reproduction
Attachments include poc.zip with:
canonical.log(contains[CALLSITE_HIT],[PROOF_MARKER])control.log(contains[CALLSITE_HIT],[NC_MARKER], does not contain[PROOF_MARKER])fix.patch(minimal validation sketch)
Expected: Multirepo repository names are treated as identifiers; a TAP 4 map file containing traversal or absolute paths is rejected (or safely normalized so that all writes stay under LocalMetadataDir).
Actual: A traversal repoName escapes LocalMetadataDir and go-tuf persists root.json under the escaped path during initialization.
Run Local Repro
rm -rf _poc
mkdir -p _poc
unzip -q -o poc.zip -d _poc
cd _poc/poc
make canonical
make control
Workarounds
- Treat TAP 4 map files as trusted configuration only (do not fetch from untrusted sources).
- Validate repo names before passing the map file to go-tuf (reject absolute paths, path separators, and traversal components like
./..). - If acceptable for the application, disable local caching to avoid writing metadata to disk (
DisableLocalCache=true).
Suggested Remediation
Validate multirepo repository names as identifiers (not paths) before using them in filepath.Join. Reject:
- Absolute paths
- Path separators (
/and\) - Traversal components (
.and..)
If it is important to accept a wider set of repo names, a safer alternative is to map repo names to a stable, validated directory name (for example via encoding or hashing) and to ensure all writes stay under the cache base directory.
Triage Questions
- Is the TAP 4 map file expected to ever be fetched from untrusted sources in supported deployments?
- Should invalid repo names be treated as a hard error (reject initialization), or as a soft error (skip that repository entry)?
Attachments
Reported by: Oleh
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/theupdateframework/go-tuf/v2 | all versions | 2.4.1go get github.com/theupdateframework/go-tuf/v2@v2.4.1 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/theupdateframework/go-tuf/v2, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/theupdateframework/go-tuf/v2 to 2.4.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-jqc5-w2xx-5vq4 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-jqc5-w2xx-5vq4 can be triaged on real exposure rather than presence alone.
Tailored to GHSA-jqc5-w2xx-5vq4. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-jqc5-w2xx-5vq4 in your dependencies?
O3 Security finds GHSA-jqc5-w2xx-5vq4 across Go dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.