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HIGH severity

CVE-2019-13126 — nats-server

HIGHFix: nats-io/nats-server#1053

CVE-2019-13126 is a high-severity (CVSS 7.5) CWE-190 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.

Integer Overflow or Wraparound in NATS Server

Also known asGHSA-jp4j-47f9-2vc3GO-2022-0852
Published
Updated
Affected
1 pkg
Patched
1 / 1
Exploits
None indexed
Exploitation data as of Oct 11, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗
1.8%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs78th percentile — riskier than 78% of all scored CVEsHighest risk
0.18%0.88%1.57%2.27%0.7%1.8%Apr 26Aug 26Oct 26

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

CVE-2019-13126 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 385,738 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.

Real-World Exposure

1 pkg affected
🐹github.com/nats-io/nats-server/v2

Real-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

An integer overflow in NATS Server before 2.0.2 allows a remote attacker to crash the server by sending a crafted request. If authentication is enabled, then the remote attacker must have first authenticated.

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
🐹Gogithub.com/nats-io/nats-server/v2all versions2.2.0go get github.com/nats-io/nats-server/v2@v2.2.0

Affected Products

1 product · 1 configurations
Application
nats-serverlinuxfoundation
< 2.0.2
range

Detection & mitigation playbook

Open-source dependency

  1. Detect

    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.

  2. Fix

    Update github.com/nats-io/nats-server/v2 to 2.2.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2019-13126 is resolved across your whole dependency graph.

  3. Workarounds

    Constrain what reaches the vulnerable code: limit the size and shape of untrusted input, isolate the affected component in a sandboxed or least-privileged process, and enable the platform's memory-safety mitigations (ASLR, stack protector, hardened allocator) so an out-of-bounds access is more likely to fail closed than to be exploitable.

Frequently Asked Questions

An integer overflow in NATS Server before 2.0.2 allows a remote attacker to crash the server by sending a crafted request. If authentication is enabled, then the remote attacker must have first authenticated.
O3 Security · Impact-Aware SCA

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CVE-2019-13126: nats-server — Fixed in 2.2.0