CVE-2026-55734Public exploitNetwork attack vectorHinoki check available

BEAM node crash via unbounded atom interning

Published Aug 1, 2026 · Updated Aug 1, 2026

Resource exhaustion in ueberauth Guardian 2.0.0 through 2.4.0 allows attackers to crash the BEAM node via crafted permission maps. encode_permissions!/1 interns every map key with String.to_atom/1 before validation, while integer values bypass permission-set validation entirely. Exploitation requires an application using Guardian.Permissions to pass attacker-influenced permission maps into encoding; exhaustion crashes every service on the node.

CVSS severity6.9
Medium
EPSS probability0.33%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Resource exhaustion in ueberauth Guardian 2.0.0 through 2.4.0 allows attackers to crash the BEAM node via crafted permission maps. encode_permissions!/1 interns every map key with String.to_atom/1 before validation, while integer values bypass permission-set validation entirely. Exploitation requires an application using Guardian.Permissions to pass attacker-influenced permission maps into encoding; exhaustion crashes every service on the node.

The record

CVE
CVE-2026-55734
Published
Aug 1, 2026
Updated
Aug 1, 2026
Vendor
ueberauth
Product
Guardian
Classifications
CWE-770, CAPEC-130, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 1, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 1, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=2.0.0 <2.4.1
  2. Affected versionversion=b7a6128ca4d0ffb7f7df5219dd982304ff9d6802 <8d4efbfc352d30f5fcfc75a4d69a795b0e472724

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

ueberauth · Guardianversion=2.0.0 <2.4.1; version=b7a6128ca4d0ffb7f7df5219dd982304ff9d6802 <8d4efbfc352d30f5fcfc75a4d69a795b0e472724

Published CVSS scores

6.9Erlang Ecosystem FoundationCVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:H
7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
6.9ueberauth GitHub Security AdvisoryCVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-770Allocation of Resources Without Limits or Throttling
CAPEC-130Excessive Allocation
T1499.004Application or System Exploitation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo