CVE-2026-41136Public exploitNetwork attack vector

Uninitialized request processing via unsupported Content-Type

Published Apr 21, 2026 · Updated Apr 22, 2026

Expected behavior violation in free5GC AMF before 1.4.3 allows remote attackers to reach request processing via unsupported Content-Type. The HTTPUEContextTransfer handler skips deserialization without setting an error for unsupported media types, then passes an uninitialized UeContextTransferRequest to the processor. Access requires the internal 5GC SBI network; secondary mandatory-field validation rejects the empty object and prevents direct state changes.

CVSS severity5.3
Medium
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

Expected behavior violation in free5GC AMF before 1.4.3 allows remote attackers to reach request processing via unsupported Content-Type. The HTTPUEContextTransfer handler skips deserialization without setting an error for unsupported media types, then passes an uninitialized UeContextTransferRequest to the processor. Access requires the internal 5GC SBI network; secondary mandatory-field validation rejects the empty object and prevents direct state changes.

The record

CVE
CVE-2026-41136
Published
Apr 21, 2026
Updated
Apr 22, 2026
Vendor
free5GC
Product
AMF
Classifications
CWE-440
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 21, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 22, 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=< 1.4.3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

free5GC · AMFversion=< 1.4.3

Published CVSS scores

5.3NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
5.5GitHubCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:P

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-440Expected Behavior Violation

Public exploit references

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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