CVE-2026-48159
CVE-2026-48159 is a CWE-506 vulnerability. O3 Security confirms whether CVE-2026-48159 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
use-reducer-async is a React useReducer with async actions. Between 2026-05-18 16:29:52 and 2026-05-19 15:26:07, the default branch contained malicious commits da72edbde5705efcec6c62e0a3dcb73687b78dc8…
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.
- A successful exploit gives an attacker total control of the affected component, not partial access.
- 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 CVE-2026-48159.
Description
use-reducer-async is a React useReducer with async actions. Between 2026-05-18 16:29:52 and 2026-05-19 15:26:07, the default branch contained malicious commits da72edbde5705efcec6c62e0a3dcb73687b78dc8 through df07d5711458d8b46e11dd7afaaa21e88cafabfb that executed remote attacker-controlled code on developer machines during npm install. The commits were removed by force-push, but local clones, forks, and direct-SHA URLs may still contain them, and npm install against an affected checkout will still execute the code today. The package was not published to npm. src/install.js was added and wired into the postinstall script. It fetched a JavaScript payload from an attacker-controlled HTTPS endpoint (configurable via an environment variable), disabled TLS verification, and evaluated the response as code with require available. Execution was deliberately skipped on CI and cloud/serverless environments, targeting developer workstations. The second-stage payload was attacker-hosted and cannot be reconstructed. Assume full compromise of anything reachable from a Node process with the user's permissions. Those who ran npm install against an affected checkout on a developer machine on or after 2026-05-18 16:29:52 should treat the machine as compromised, rotate every credential the machine could reach, audit account activity since 2026-05-18 16:29:52, and clean local clones.
Detection & mitigation playbook
VulnerabilityDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for the affected component. 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.
Remediation status
No patched version of the affected component has shipped for CVE-2026-48159 yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.
Mitigate without a patch
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-2026-48159 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-2026-48159. 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-2026-48159 in your dependencies?
O3 detects CVE-2026-48159 across dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.