CVE-2026-59873
Fix: isaacs/node-tar@2812e93CVE-2026-59873 is a CWE-770 vulnerability in tar. O3 Security confirms whether CVE-2026-59873 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
node-tar: Decompression/parse DoS via unlimited input
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.
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-59873.
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.
tarnpmDescription
node-tar is a tar archive manipulation library for Node.js. Prior to 7.5.19, node-tar does not enforce hard upper bounds on total decompressed data, entry counts, or decompression ratio in extraction and parsing paths such as src/extract.ts, allowing a small crafted gzip bomb to exhaust disk space and CPU. This issue is fixed in version 7.5.19.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | tar | all versions | 7.5.19 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for tar. 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 tar to 7.5.19 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-59873 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 CVE-2026-59873 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 CVE-2026-59873. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
This vulnerability in node-tar is rated as Important. A remote attacker can exploit the lack of strict limits on decompressed data and entry counts within the library's archive processing to craft a gzip bomb. This can lead to a denial of service by exhausting system resources such as disk space and CPU, making the…
Frequently Asked Questions
Is CVE-2026-59873 in your dependencies?
O3 detects CVE-2026-59873 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.