GHSA-qq3r-w4hj-gjp6 is a high-severity (CVSS 7.5) Path Traversal vulnerability in chainguard.dev/apko. O3 Security confirms whether GHSA-qq3r-w4hj-gjp6 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
apko dirFS has a symlink-following path traversal that allows multiple entry points to escape the build root
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for GHSA-qq3r-w4hj-gjp6.
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-qq3r-w4hj-gjp6 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 356,453 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
chainguard.dev/apkoReal-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
Impact
A crafted .apk could install a TypeSymlink tar entry whose target pointed outside the build root, and a subsequent directory-creation or file-write entry in the same or later archive could traverse that symlink to reach host paths the build user could write to. The root cause was the sanitizePath helper in pkg/apk/fs/rwosfs.go, which rejected only lexical .. traversal and did not resolve or refuse symlinks. Every disk-backed DirFS method that handed its caller-supplied path to a symlink-following stdlib call — ReadFile, WriteFile, Chmod, Chown, Chtimes, MkdirAll, Mkdir, and Mknod — was affected. The reachable primitive from a malicious APK during tar extraction is the MkdirAll / Mkdir / WriteFile chain via apko build-cpio and disk-backed consumers such as melange; the remaining sinks are reachable by direct callers of the pkg/apk/fs package. The in-memory tarfs install path used by apko build, apko publish, and apko build-minirootfs is not affected.
Patches
Fixed in apko v1.2.5 by #2187 / commit f5a96e1, which scopes all DirFS operations through a Go 1.24 *os.Root. The sanitizePath helper has been removed; *os.Root refuses traversal via .., absolute-target symlinks, relative-target symlinks, and hardlinks by construction. Regression tests in pkg/apk/apk/path_traversal_test.go cover each composite primitive.
Workarounds
No complete workaround. Operators running pre-1.2.5 apko (or downstream tools such as melange that embed pre-1.2.5 pkg/apk/fs) should upgrade. Consuming only APKs from trusted, signed sources reduces but does not eliminate exposure.
Resources
- https://github.com/chainguard-dev/apko/pull/2187
- https://github.com/chainguard-dev/apko/commit/f5a96e1299ac81c7ea9441705ec467688086f442
- https://github.com/chainguard-dev/apko/releases/tag/v1.2.5
- Related: GHSA-5g94-c2wx-8pxw (CVE-2026-25121) — prior lexical
..traversal fix
Credits
apko thanks Oleh Konko (@1seal from 1seal.org) for the initial report of the symlink-escape class, and to @Xh081iX for a follow-up set of reports covering additional reachable primitives (ReadFile, Chmod/Chown, Mknod, MkdirAll/Mkdir) that shaped the comprehensive fix.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | chainguard.dev/apko | ≥ 0.14.8&&< 1.2.5 | 1.2.5 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for chainguard.dev/apko. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update chainguard.dev/apko to 1.2.5 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-qq3r-w4hj-gjp6 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 pinpoints whether GHSA-qq3r-w4hj-gjp6 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-qq3r-w4hj-gjp6. 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-qq3r-w4hj-gjp6 in your dependencies?
O3 detects GHSA-qq3r-w4hj-gjp6 across Go dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.