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Fencer Intel
critical 9.5

CVE-2026-104848 json

Tinypool: Prototype Pollution gadget in worker options leads to Remote Code Execution

published last mo. modified last mo. also GHSA-5gmw-xhrv-c9v3 , EUVD-2026-91718

cvss
9.5
version 4.0, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 42%
public exploits
0
none known

Summary

Tinypool is a minimal Node.js worker thread pool implementation. Prior to 2.1.1, Tinypool constructs ThreadPool.options from a normal options object and reads the execArgv and env worker options in dist/index.js, allowing values inherited from a polluted Object.prototype to be copied into own properties and passed to worker_threads.Worker. An attacker who can first pollute either property can cause each newly spawned worker to load attacker-selected JavaScript through command-line preload arguments or NODE_OPTIONS, resulting in code execution with the host process's privileges and possible access to CI secrets, signing material, or build artifacts. This issue is fixed in version 2.1.1.

Patch / fix

  • npm tinypool 2.1.1

Is CVE-2026-104848 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-104848 updated cvss 8.1

tinypool: tinypool: arbitrary code execution via prototype pollution in worker options

  • Red Hat AMQ Broker 7 amq-broker-maven-repository.zip
    affected: workaround, no fix available
  • Red Hat Build of Podman Desktop rh-podman-desktop
    affected: workaround, no fix planned “Will not fix”
  • Red Hat AMQ Broker 7 amq-broker-bin.zip Red Hat Ansible Automation Platform 2 automation-gateway, automation-platform-ui, ansible-automation-platform-26/gateway-rhel9
    not affected: vulnerable code not present
  • Red Hat Hardened Images jaeger, prometheus3.13, opentelemetry-collector, opentelemetry-collector-k8s, opentelemetry-collector-contrib Red Hat JBoss Enterprise Application Platform 8 jboss-eap-runtime-maven-repository.zip, jboss-eap.1-runtime-maven-repository.zip Red Hat JBoss Enterprise Application Platform Expansion Pack jboss-eap-runtime-maven-repository.zip, jboss-eap.1-runtime-maven-repository.zip
    not affected: component not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
total
Assessed
last mo.

Exploit prediction

0.50% chance of exploitation in the next 30 days, higher than 42% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • github.com https://github.com/tinylibs/tinypool/security/advisories/GHSA-5gmw-xhrv-c9v3 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 4.0 9.5 CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H
CNA 4.0 9.5 CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Affected packages

ecosystem package affected fixed in
npm tinypool
<2.1.1
2.1.1

Affected products

  • tinylibs tinypool

Classification

Weakness
  • CWE-1321 Improperly Controlled Modification of Object Prototype Attributes

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.