CVE-2026-41136

free5GC AMF provides Access & Mobility Management Function (AMF) for free5GC, an an open-source project for 5th generation (5G) mobile core networks. Prior to version 1.4.3, the HTTPUEContextTransfer handler in internal/sbi/api_communication.go does not include a default case in the Content-Type switch statement. When a request arrives with an unsupported Content-Type, the deserialization step is silently skipped, err remains nil, and the processor is invoked with a completely uninitialized UeContextTransferRequest object. Version 1.4.3 contains a fix.

free5GC AMF provides Access & Mobility Management Function (AMF) for free5GC, an an open-source project for 5th generation (5G) mobile core networks. Prior to version 1.4.3, the HTTPUEContextTransfer handler in internal/sbi/api_communication.go does not include a default case in the Content-Type switch statement. When a request arrives with an unsupported Content-Type, the deserialization step is silently skipped, err remains nil, and the processor is invoked with a completely uninitialized UeContextTransferRequest object. Version 1.4.3 contains a fix.

Summary

The HTTPUEContextTransfer handler in internal/sbi/api_communication.go does not include a default case in the Content-Type switch statement. When a request arrives with an unsupported Content-Type, the deserialization step is silently skipped, err remains nil, and the processor is invoked with a completely uninitialized UeContextTransferRequest object.

Details

In internal/sbi/api_communication.go, the HTTPUEContextTransfer function handles the Content-Type header with a switch statement that only covers application/json and multipart/related:

switch str[0] {
case applicationjson:
    err = openapi.Deserialize(ueContextTransferRequest.JsonData, requestBody, contentType)
case multipartrelate:
    err = openapi.Deserialize(&ueContextTransferRequest, requestBody, contentType)
// no default case
}

if err != nil {
    // skipped entirely when Content-Type is unsupported
    c.JSON(http.StatusBadRequest, rsp)
    return
}

s.Processor().HandleUEContextTransferRequest(c, ueContextTransferRequest)

This is inconsistent with the two analogous handlers in the same file, HTTPCreateUEContext and HTTPN1N2MessageTransfer, which both correctly include a default branch:

default:
    err = fmt.Errorf("wrong content type")

The fix is simply to add the same default case to HTTPUEContextTransfer.

PoC

With a free5GC deployment running, send a POST request to the UE context transfer endpoint using any unsupported Content-Type (e.g. text/plain):

curl -s -X POST "http://<AMF_IP>/namf-comm/v1/ue-contexts/<ueContextId>/transfer" \\
  -H "Content-Type: text/plain" \\
  -d '{"test":"data"}' \\
  -i

Expected (correct) behavior: 400 Bad Request from the SBI layer, rejecting the request due to unsupported Content-Type — consistent with HTTPCreateUEContext.

Actual (observed) behavior: The SBI-layer error check is bypassed and the processor is reached with an empty request object, returning:

HTTP/1.1 400 Bad Request
{"status": 400, "cause": "MANDATORY_IE_MISSING"}

The MANDATORY_IE_MISSING cause originates from the processor's internal validation, not from the SBI handler — confirming the processor was called with an uninitialized struct.

Impact

The endpoint is an inter-NF SBI API used during AMF-to-AMF UE context handover. It is not directly reachable from external UEs and requires access to the internal 5GC SBI network. The processor's secondary mandatory field validation prevents any unintended state modification, so there is no direct exploitability. However, the SBI handler layer is the intended first line of defense — relying on the processor to compensate for a missing input check increases fragility and violates defense in depth. Any future change to the processor's validation logic could inadvertently expose the system to processing completely empty request objects.

free5GC AMF provides Access & Mobility Management Function (AMF) for free5GC, an an open-source project for 5th generation (5G) mobile core networks. Prior to version 1.4.3, the HTTPUEContextTransfer handler in internal/sbi/api_communication.go does not include a default case in the Content-Type switch statement. When a request arrives with an unsupported Content-Type, the deserialization step is silently skipped, err remains nil, and the processor is invoked with a completely uninitialized UeContextTransferRequest object. Version 1.4.3 contains a fix.

free5GC AMF provides Access & Mobility Management Function (AMF) for free5GC, an an open-source project for 5th generation (5G) mobile core networks. Prior to version 1.4.3, the HTTPUEContextTransfer handler in internal/sbi/api_communication.go does not include a default case in the Content-Type switch statement. When a request arrives with an unsupported Content-Type, the deserialization step is silently skipped, err remains nil, and the processor is invoked with a completely uninitialized UeContextTransferRequest object. Version 1.4.3 contains a fix.

Summary

The HTTPUEContextTransfer handler in internal/sbi/api_communication.go does not include a default case in the Content-Type switch statement. When a request arrives with an unsupported Content-Type, the deserialization step is silently skipped, err remains nil, and the processor is invoked with a completely uninitialized UeContextTransferRequest object.

Details

In internal/sbi/api_communication.go, the HTTPUEContextTransfer function handles the Content-Type header with a switch statement that only covers application/json and multipart/related:

switch str[0] {
case applicationjson:
    err = openapi.Deserialize(ueContextTransferRequest.JsonData, requestBody, contentType)
case multipartrelate:
    err = openapi.Deserialize(&ueContextTransferRequest, requestBody, contentType)
// no default case
}

if err != nil {
    // skipped entirely when Content-Type is unsupported
    c.JSON(http.StatusBadRequest, rsp)
    return
}

s.Processor().HandleUEContextTransferRequest(c, ueContextTransferRequest)

This is inconsistent with the two analogous handlers in the same file, HTTPCreateUEContext and HTTPN1N2MessageTransfer, which both correctly include a default branch:

default:
    err = fmt.Errorf("wrong content type")

The fix is simply to add the same default case to HTTPUEContextTransfer.

PoC

With a free5GC deployment running, send a POST request to the UE context transfer endpoint using any unsupported Content-Type (e.g. text/plain):

curl -s -X POST "http://<AMF_IP>/namf-comm/v1/ue-contexts/<ueContextId>/transfer" \\
  -H "Content-Type: text/plain" \\
  -d '{"test":"data"}' \\
  -i

Expected (correct) behavior: 400 Bad Request from the SBI layer, rejecting the request due to unsupported Content-Type — consistent with HTTPCreateUEContext.

Actual (observed) behavior: The SBI-layer error check is bypassed and the processor is reached with an empty request object, returning:

HTTP/1.1 400 Bad Request
{"status": 400, "cause": "MANDATORY_IE_MISSING"}

The MANDATORY_IE_MISSING cause originates from the processor's internal validation, not from the SBI handler — confirming the processor was called with an uninitialized struct.

Impact

The endpoint is an inter-NF SBI API used during AMF-to-AMF UE context handover. It is not directly reachable from external UEs and requires access to the internal 5GC SBI network. The processor's secondary mandatory field validation prevents any unintended state modification, so there is no direct exploitability. However, the SBI handler layer is the intended first line of defense — relying on the processor to compensate for a missing input check increases fragility and violates defense in depth. Any future change to the processor's validation logic could inadvertently expose the system to processing completely empty request objects.

free5GC AMF: Missing default case in Content-Type switch in HTTPUEContextTransfer in github.com/free5gc/amf

This update for govulncheck-vulndb fixes the following issues:

• Update to version 0.0.20260723T184607 2026-07-23T18:46:07Z (jsc#PED-11136).

Go CVE Numbering Authority IDs added or updated with aliases:

• GO-2026-4730 CVE-2026-33022 GHSA-cv4x-93xx-wgfj
• GO-2026-4761 CVE-2026-33211 GHSA-j5q5-j9gm-2w5c
• GO-2026-5102 CVE-2026-45021 GHSA-3vcp-chfh-f6r2
• GO-2026-5272 CVE-2026-40938 GHSA-94jr-7pqp-xhcq
• GO-2026-5486 CVE-2026-40924 GHSA-m2cx-gpqf-qf74
• GO-2026-5542 CVE-2026-40090 GHSA-pj97-4p9w-gx3q
• GO-2026-5630 CVE-2026-25542 GHSA-rmx9-2pp3-xhcr
• GO-2026-5643 CVE-2026-40923 GHSA-rx35-6rhx-7858
• GO-2026-5675 CVE-2026-41492 GHSA-vvf7-6rmr-m29q
• GO-2026-5711 CVE-2026-40161 GHSA-wjxp-xrpv-xpff
• GO-2026-5746 CVE-2026-41567 GHSA-x86f-5xw2-fm2r
• GO-2026-5749 CVE-2026-41328 GHSA-x92x-px7w-4gx4
• GO-2026-5837 CVE-2026-44840 GHSA-q2m9-6jp9-c6mc
• GO-2026-5929 CVE-2026-44342 GHSA-26v7-h57m-gh9m
• GO-2026-5930 CVE-2026-33655 GHSA-6qcr-qxgr-m7fv
• GO-2026-5933 GHSA-3g4q-2f67-2gvh
• GO-2026-5934 GHSA-59qp-cfj3-rp64
• GO-2026-5935 GHSA-7856-g3gv-9wq8
• GO-2026-5936 CVE-2026-53552 GHSA-26rh-24rg-j3vv
• GO-2026-5937 CVE-2026-53508 GHSA-2jcc-mxv7-p3f9
• GO-2026-5938 CVE-2026-53553 GHSA-4g5x-hcwm-82jw
• GO-2026-5939 CVE-2026-10517 GHSA-698x-9w2p-7vvp
• GO-2026-5940 CVE-2026-53572 GHSA-6w3m-4hhp-775q
• GO-2026-5941 CVE-2026-53487 GHSA-gvhc-wv3v-7pf8
• GO-2026-5942 CVE-2026-46600
• GO-2026-5944 CVE-2026-50197 GHSA-659f-rgp5-w4wf
• GO-2026-5945 CVE-2026-6815 GHSA-rmxx-v9rj-vpvg
• GO-2026-5946 CVE-2026-52831 GHSA-v5px-423j-pf7p
• GO-2026-5947 CVE-2026-53649 GHSA-xqhv-chqm-fhcc
• GO-2026-5948 CVE-2026-50554 GHSA-588f-fvcv-xhvf
• GO-2026-5949 CVE-2026-50553 GHSA-rqrh-8wpv-x7hh
• GO-2026-5950 CVE-2026-53602 GHSA-339v-266x-79xr
• GO-2026-5951 CVE-2026-10219 GHSA-6jm8-4fhr-5w64
• GO-2026-5952 CVE-2026-49834 GHSA-9vcr-p3rj-q5q6
• GO-2026-5953 CVE-2026-9094 GHSA-c9w5-qp6m-m395
• GO-2026-5956 CVE-2026-55252 GHSA-h5g6-xmh4-hc37
• GO-2026-5957 CVE-2026-54158 GHSA-5xfx-xj4h-5p7r
• GO-2026-5958 CVE-2026-54068 GHSA-gcm7-57gf-953c
• GO-2026-5959 CVE-2026-54072 GHSA-h29v-hj44-q8cv
• GO-2026-5961 CVE-2026-54069 GHSA-hvr9-72v2-fff3
• GO-2026-5962 CVE-2026-54088 GHSA-m93h-4hw7-5qcm
• GO-2026-5963 CVE-2026-54067 GHSA-mvjr-vv3c-w4qv
• GO-2026-5964 CVE-2026-54066 GHSA-p4m3-mgmm-c664
• GO-2026-5965 CVE-2026-54070 GHSA-w7cg-whh7-xp28
• GO-2026-5966 CVE-2026-54089 GHSA-xqp3-jq6g-x3qm
• GO-2026-5967 CVE-2026-50551 GHSA-56mp-4f3v-fgj2
• GO-2026-5968 CVE-2026-54174 GHSA-fpg8-7664-jc5q
• GO-2026-5969 GHSA-g936-7jqj-mwv8
• GO-2026-5970 CVE-2026-56852
• GO-2026-5973 CVE-2026-54250 GHSA-jxr7-mqhw-9p98
• GO-2026-5974 CVE-2026-44300 GHSA-wmj8-9953-vff5
• GO-2026-5975 CVE-2026-50018 GHSA-42j2-w334-qxw7
• GO-2026-5976 CVE-2026-50141 GHSA-g7mm-9vx7-jm7h
• GO-2026-5977 CVE-2026-50013 GHSA-qrh4-p6v4-mrfg
• GO-2026-5978 CVE-2026-50125 GHSA-qw5r-ppcg-f8rj
• GO-2026-5979 CVE-2026-50006 GHSA-xrcf-6jh3-ggvx
• GO-2026-5980 CVE-2026-50158 GHSA-2c7f-fxww-6w6c
• GO-2026-5981 GHSA-mqxv-9rm6-w8qc
• GO-2026-5982 GHSA-pqg7-v6wh-3pfp
• GO-2026-5984 CVE-2026-53604 GHSA-2p2f-px33-4vv5
• GO-2026-5985 GHSA-7rx3-5wx3-5v76
• GO-2026-5986 CVE-2026-61699 GHSA-cm26-5974-52h8
• GO-2026-5987 CVE-2026-55513 GHSA-g4x6-jcvr-9m3g
• GO-2026-5988 CVE-2026-54628 GHSA-hwrq-8wxh-q4xv
• GO-2026-5989 CVE-2026-55512 GHSA-m3cx-mwpg-32jg
• GO-2026-5990 CVE-2026-54629 GHSA-mf78-3rpf-r784
• GO-2026-5991 CVE-2026-53603 GHSA-q4vm-pq3q-8wgq
• GO-2026-5992 CVE-2026-61549 GHSA-qf34-295c-26v8
• GO-2026-5996 CVE-2026-54450 GHSA-pph6-vfjv-vpjw
• GO-2026-5997 CVE-2026-54452 GHSA-xgch-x3mx-cm3c
• GO-2026-5998 CVE-2026-54495 GHSA-398h-7f66-3h4p
• GO-2026-5999 CVE-2026-10814 GHSA-jh6h-v6mp-h22v
• GO-2026-6002 CVE-2026-58196 GHSA-pr64-jmmf-jp54
• GO-2026-6003 CVE-2026-53714 GHSA-22xc-xg2r-9j7v
• GO-2026-6004 CVE-2026-52833 GHSA-3v79-m2cg-89ww
• GO-2026-6005 CVE-2026-53715 GHSA-8fv2-88gg-hm7q
• GO-2026-6006 CVE-2026-53716 GHSA-cxpq-8v7q-cg56 *…