CVE-2026-18948 — Red Hat
CRITICALCVE-2026-18948 is a critical-severity (CVSS 9.9) Deserialization of Untrusted Data vulnerability. No vendor fix is recorded yet; mitigation options are listed below.
A flaw was found in Feast. The system improperly deserializes user-defined functions (UDFs) stored in its registry, which are serialized using the 'dill' library. This allows a remote…
Exploitation Status
No confirmed exploitation observed yet
- 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-2026-18948.
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
CVE-2026-18948 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 378,567 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.
Description
A flaw was found in Feast. The system improperly deserializes user-defined functions (UDFs) stored in its registry, which are serialized using the 'dill' library. This allows a remote attacker to store a malicious UDF, leading to unauthenticated arbitrary code execution on the feature server in default configurations. An authenticated attacker can also achieve arbitrary code execution on the registry server by bypassing authorization checks during deserialization. This vulnerability can result in cross-tenant data access and lateral movement within the system.
Detection & mitigation playbook
VulnerabilityDetect
Identify every host running the affected component and compare the installed build against the fixed version below — for source-built or distro-packaged software the version string, not a lockfile, is the source of truth (`dpkg -l`, `rpm -q`, or the binary's own `--version`). Because remote code execution targets the running service rather than your application code, O3 also flags the exploit behaviour from runtime telemetry and egress traffic.
Remediation status
No fixed release is recorded for CVE-2026-18948 yet. Track the upstream advisory, and apply the exposure-reduction steps below in the meantime.
Mitigate without a patch
Reduce reachability while you patch: restrict network access to the service to trusted sources, disable or gate the affected component where your deployment allows it, and add a WAF/IPS signature if one exists for CVE-2026-18948. O3's runtime protection blocks the deserialization of untrusted data flaw at execution, which holds the line on hosts you cannot patch immediately.
How O3 protects you
O3 detects and blocks CVE-2026-18948 exploitation at runtime with eBPF exploit-chain detection, plus L7 egress monitoring that catches a post-exploitation callback and cuts the attacker's outbound channel.
Tailored to CVE-2026-18948. 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 Critical vulnerability in Feast, as deployed within Red Hat OpenShift AI, allows for remote code execution due to unsafe deserialization of user-defined functions. An unauthenticated attacker can achieve RCE on the feature-server pod in default configurations, leading to cross-tenant data access and potential…
| Product | Fixed in | Advisory |
|---|---|---|
| Red Hat OpenShift AI 2.25 | rhoai/odh-feature-server-rhel9:1786110051 | RHSA-2026:53261 |
| Red Hat OpenShift AI 3.3 | rhoai/odh-feature-server-rhel9:1786110033 | RHSA-2026:53263 |
| Red Hat OpenShift AI 3.4 | rhoai/odh-feature-server-rhel9:1786107278 | RHSA-2026:53262 |
| Red Hat OpenShift AI 3.4 | rhoai/odh-feature-server-rhel9:1787068065 | RHSA-2026:60520 |
Frequently Asked Questions
Is CVE-2026-18948 in your dependencies?
O3 Security finds CVE-2026-18948 across dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.