CVE-2026-54894 ueberauth CVE debrief

Who should care

Users of ueberauth guardian, especially those who handle user-supplied input or tenant identifiers, should be aware of this vulnerability and take steps to mitigate it. This includes reviewing system resources and atom table usage, implementing input validation and sanitization, and considering rate limiting or throttling for suspicious activity. Security teams and vulnerability management teams should also be aware of this issue and plan accordingly.

Technical summary

The vulnerability exists in the Guardian.Plug.Keys module, where arbitrary binaries are converted to atoms using String.to_atom/1. This allows an attacker to create an unbounded number of atoms, potentially leading to atom table exhaustion and BEAM node crashes. The issue affects guardian versions from 0.1.0 before 2.4.1. Users should be aware of this vulnerability and take steps to mitigate it, especially those who handle user-supplied input or tenant identifiers.

Defensive priority

Medium priority due to potential for denial-of-service attacks

Recommended defensive actions

• Update guardian to version 2.4.1 or later
• Implement input validation and sanitization for user-supplied data
• Monitor system resources and atom table usage
• Consider implementing rate limiting or throttling for suspicious activity
• Review compensating controls for exposed systems while remediation is scheduled and verified
• Check relevant monitoring, detection, and logs for exposed assets that need extra review
• Track exceptions, retest remediated assets, and close the item only after evidence is documented

Evidence notes

Evidence is based on official CVE and NVD records, as well as source references from Erlef and GitHub. However, details about the vendor and affected products are limited. The vulnerability arises from the conversion of attacker-influenced binary input into atoms using String.to_atom/1, leading to potential atom table exhaustion and BEAM node crashes. Users should verify affected product deployments, review official advisories, and plan vendor-supported updates or mitigations.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.