CVE-2026-55785Network attack vector

Authentication-material disclosure via INFO logging and timing

Published Aug 28, 2026 · Updated Aug 28, 2026

Sensitive-data exposure in free5GC AUSF before 1.4.5 allows attackers with log access to read expected authentication values. Auth5gAkaComfirmRequestProcedure logs XRES* at INFO and compares RES* with strings.EqualFold, while EapAuthComfirmRequestProcedure uses bytes.Equal and ordinary string equality for MAC and response values. Log disclosure requires AUSF log access; a practical remote HTTP timing oracle was not demonstrated because SBI noise overwhelmed the mismatch-dependent signal.

CVSS severity3.7
Low
EPSS probability0.28%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Sensitive-data exposure in free5GC AUSF before 1.4.5 allows attackers with log access to read expected authentication values. Auth5gAkaComfirmRequestProcedure logs XRES* at INFO and compares RES* with strings.EqualFold, while EapAuthComfirmRequestProcedure uses bytes.Equal and ordinary string equality for MAC and response values. Log disclosure requires AUSF log access; a practical remote HTTP timing oracle was not demonstrated because SBI noise overwhelmed the mismatch-dependent signal.

The record

CVE
CVE-2026-55785
Published
Aug 28, 2026
Updated
Aug 28, 2026
Vendor
free5GC
Product
free5GC
Classifications
CWE-532, CWE-385, CWE-208, T1552.001
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 28, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 28, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

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

  1. Affected versionversion=< 1.4.5

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

free5GC · free5GCversion=< 1.4.5

Published CVSS scores

3.7GitHubCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N

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.

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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 exploitUnconfirmed

Weakness, pattern, technique

CWE-532Insertion of Sensitive Information into Log File
CWE-385Covert Timing Channel
CWE-208Observable Timing Discrepancy
T1552.001Unsecured Credentials: Credentials In Files

Public exploit references

No public exploit references are available in this record.

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

Technologies

Your stack

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Your stack

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