GHSA-6h3m-36w8-hv68 is a medium-severity (CVSS 6.5) Path Traversal vulnerability in github.com/nats-io/nats-server/v2. A fix is available for github.com/nats-io/nats-server/v2 — see the affected versions and patch details below.
Arbitrary file write in nats-server
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-6h3m-36w8-hv68 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 377,166 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/nats-io/nats-server/v2🐹github.com/nats-io/nats-streaming-serverReal-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
(This document is canonically: https://advisories.nats.io/CVE/CVE-2022-26652.txt)
Background
NATS.io is a high performance open source pub-sub distributed communication technology, built for the cloud, on-premise, IoT, and edge computing.
JetStream is the optional RAFT-based resilient persistent feature of NATS.
Problem Description
The JetStream streams can be backed up and restored via NATS. The backup format is a tar archive file. Inadequate checks on the filenames within the archive file permit a so-called "Zip Slip" attack in the stream restore.
NATS nats-server through 2022-03-09 (fixed in release 2.7.4) did not correctly sanitize elements of the archive file, thus a user of NATS could cause the NATS server to write arbitrary content to an attacker-controlled filename.
Affected versions
NATS Server:
- 2.2.0 up to and including 2.7.3.
- Introduced with JetStream Restore functionality
- Fixed with nats-io/nats-server: 2.7.4
- Docker image: nats https://hub.docker.com/_/nats
- NB users of OS package files from our releases: a change in goreleaser defaults, discovered late in the release process, moved the install directory from /usr/local/bin to /usr/bin; we are evaluating the correct solution for subsequent releases, but not recutting this release.
NATS Streaming Server
- 0.15.0 up to and including 0.24.2
- Fixed with nats-io/nats-streaming-server: 0.24.3
- Embeds a nats-server, but this server is the old approach which JetStream replaces, so unlikely (but not impossible) to be configured with JS support
Workarounds
- Disable JetStream for untrusted users.
- If only one NATS account uses JetStream, such that cross-user attacks are not an issue, and any user in that account with access to the JetStream API is fully trusted anyway, then appropriate sandboxing techniques will prevent exploit.
- Eg, with systemd, the supplied util/nats-server-hardened.service example configuration demonstrates that NATS runs fine as an unprivileged user under ProtectSystem=strict and PrivateTmp=true restrictions; by only opening a ReadWritePaths hole for the JetStream storage area, the impact of this vulnerability is limited.
Solution
Upgrade the NATS server to at least 2.7.4.
We fully support the util/nats-server-hardened.service configuration for running a NATS server and encourage this approach.
Credits
This issue was reported (on 2022-03-07) to the NATS Maintainers by
Yiming Xiang, TIANJI LAB of NSFOCUS.
Thank you / 谢谢你！
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/nats-io/nats-server/v2 | ≥ 2.2.0&&< 2.7.4 | 2.7.4go get github.com/nats-io/nats-server/v2@v2.7.4 |
| 🐹Go | github.com/nats-io/nats-streaming-server | ≥ 0.15.0&&< 0.24.3 | 0.24.3go get github.com/nats-io/nats-streaming-server@v0.24.3 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/nats-io/nats-server/v2, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/nats-io/nats-server/v2 to 2.7.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-6h3m-36w8-hv68 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-6h3m-36w8-hv68 can be triaged on real exposure rather than presence alone.
Tailored to GHSA-6h3m-36w8-hv68. 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-6h3m-36w8-hv68 in your dependencies?
O3 Security finds GHSA-6h3m-36w8-hv68 across Go dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.