free5gc UDR improper path validation allows unauthenticated deletion of Traffic Influence Subscriptions

CISA KEV is observed exploitation evidence. FIRST EPSS is a dated prediction of exploitation in the next 30 days. Missing scores are unknown. This collector requests predictions only for explicit CVE aliases in the public NuGet archive; Microsoft release views retain their existing prediction scope.

No collected risk observation for these identifiers. This does not establish absence of exploitation or a zero probability.

free5GC is an open-source implementation of the 5G core network. In versions 1.4.2 and below of the UDR service, the handler for deleting Traffic Influence Subscriptions checks whether the influenceId path segment equals subs-to-notify, but does not return after sending the HTTP 404 response when validation fails. Execution continues and the subscription is deleted regardless. An unauthenticated attacker with access to the 5G Service Based Interface can delete arbitrary Traffic Influence Subscriptions by supplying any value for the influenceId path segment, while the API misleadingly returns a 404 Not Found response. A patched version was not available at the time of publication.

Source published

16 Apr 2026 21:40:03 UTC

Source modified

18 Apr 2026 02:46:14 UTC

Observed here

23 Oct 2026 15:48:27 UTC

Source terms

CVE Program Terms of Use

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: cve-program · CVE Program Terms of Use. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 4.0 · 8.7 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

free5GC is an open-source implementation of the 5G core network. In versions 1.4.2 and below of the UDR service, the handler for deleting Traffic Influence Subscriptions checks whether the influenceId path segment equals subs-to-notify, but does not return after sending the HTTP 404 response when validation fails. Execution continues and the subscription is deleted regardless. An unauthenticated attacker with access to the 5G Service Based Interface can delete arbitrary Traffic Influence Subscriptions by supplying any value for the influenceId path segment, while the API misleadingly returns a 404 Not Found response. A patched version was not available at the time of publication.

Source published

Apr 16, 2026, 9:40:03 PM (timezone not stated)

Source modified

Apr 18, 2026, 2:46:14 AM (timezone not stated)

Observed here

7 Nov 2026 08:36:43 UTC

Source terms

ENISA EUVD · source terms and attribution apply

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: euvd · ENISA EUVD · source terms and attribution apply. Source text is retained; field grouping and change labels are provided by ChangeIntel.

EUVD CVSS 4.0 · 8.7 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

free5GC is an open-source implementation of the 5G core network. In versions 1.4.2 and below of the UDR service, the handler for deleting Traffic Influence Subscriptions checks whether the influenceId path segment equals subs-to-notify, but does not return after sending the HTTP 404 response when validation fails. Execution continues and the subscription is deleted regardless. An unauthenticated attacker with access to the 5G Service Based Interface can delete arbitrary Traffic Influence Subscriptions by supplying any value for the influenceId path segment, while the API misleadingly returns a 404 Not Found response. A patched version was not available at the time of publication.

Source published

16 Apr 2026 22:16:38 UTC

Source modified

20 Oct 2026 16:13:56 UTC

Observed here

25 Oct 2026 09:17:24 UTC

Source terms

NIST NVD usage terms; underlying source attribution retained

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: nvd · NIST NVD usage terms; underlying source attribution retained. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 4.0 · [email protected] · Secondary · 8.7 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

CVSS 3.1 · [email protected] · Primary · 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

### Summary An improper path validation vulnerability in the UDR service allows any unauthenticated attacker with access to the 5G Service Based Interface (SBI) to delete Traffic Influence Subscriptions by supplying an arbitrary value in place of the expected `subs-to-notify` path segment. ### Details The endpoint `DELETE /nudr-dr/v2/application-data/influenceData/{influenceId}/{subscriptionId}` is intended to only operate on Traffic Influence Subscription resources when `influenceId` is exactly `subs-to-notify`. In the free5GC UDR implementation, the path validation is present but ineffective because the handler does not return after sending the HTTP 404 response. The request handling flow is: 1. The function `HandleApplicationDataInfluenceDataSubsToNotifySubscriptionIdDelete` in `./free5gc_4-2-1/free5gc/NFs/udr/internal/sbi/api_datarepository.go` checks whether `influenceId != "subs-to-notify"`. 2. If the value is different, it calls `c.String(http.StatusNotFound, "404 page not found")`, **but it does not return afterwards**. 3. Execution continues and the handler still calls `s.Processor().ApplicationDataInfluenceDataSubsToNotifySubscriptionIdDeleteProcedure(c, subscriptionId)`. 4. The processor deletes the subscription identified by `subscriptionId` even though the path is invalid and the request should have been rejected. As a result, an attacker can send a request to an invalid path, receive an apparent `404 page not found` response, and still successfully delete the target subscription. The missing `return` after sending the 404 response in `api_datarepository.go` is the root cause of this vulnerability. ### PoC No authentication is required. Only a valid `subscriptionId` is needed. ```bash # Create a subscription to obtain a valid subscriptionId curl -v -X POST "http://<udr-host>/nudr-dr/v2/application-data/influenceData/subs-to-notify" \ -H "Content-Type: application/json" \ -d '{ "notificationUri":"http://evil.com/notify", "dnns":["internet"], "supis":["imsi-222777483957498"] }' ``` Example response: ``` HTTP/1.1 201 Created ``` Then delete it through an invalid path: ```bash curl -v -X DELETE "http://<udr-host>/nudr-dr/v2/application-data/influenceData/WRONGID/87615e16" ``` Response: ``` HTTP/1.1 404 Not Found 404 page not found ``` Now verify that the subscription was actually deleted: ```bash curl -v "http://<udr-host>/nudr-dr/v2/application-data/influenceData/subs-to-notify/87615e16" ``` Response: ```json {"title":"User not found","status":404,"cause":"USER_NOT_FOUND"} ``` ### Impact This is an unauthenticated unauthorized delete vulnerability. Any attacker with network access to the SBI can delete Traffic Influence Subscriptions by knowing or guessing a valid subscriptionId. This can disrupt policy-related notification workflows and remove active subscription state from the UDR. In addition, the attack is harder to detect because the API returns a misleading 404 Not Found response even when the deletion is actually performed. Impacted deployments: any free5GC instance where the SBI is reachable by untrusted parties (e.g., misconfigured network segmentation, rogue NF, or compromised internal host). ### Patch The vulnerability has been confirmed patched by adding the missing return statement in NFs/udr/internal/sbi/api_datarepository.go, function HandleApplicationDataInfluenceDataSubsToNotifySubscriptionIdDelete: ```go if influenceId != "subs-to-notify" { c.String(http.StatusNotFound, "404 page not found") return } ``` With the patch applied, requests using an invalid influenceId now correctly return HTTP 404 and do not delete the targeted subscription.

Source published

14 Apr 2026 20:00:24 UTC

Source modified

21 Jul 2026 14:03:13 UTC

Observed here

24 Oct 2026 13:19:41 UTC

Source terms

GitHub Advisory Database · CC-BY-4.0

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · GitHub Advisory Database · CC-BY-4.0. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS_V3 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

CVSS_V4 · CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

Publisher rating · HIGH

free5gc UDR improper path validation allows unauthenticated deletion of Traffic Influence Subscriptions in github.com/free5gc/udr

Source published

25 Jun 2026 18:43:19 UTC

Source modified

25 Jun 2026 19:45:38 UTC

Observed here

24 Oct 2026 13:19:41 UTC

Source terms

OSV · upstream source license applies

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · OSV · upstream source license applies. Source text is retained; field grouping and change labels are provided by ChangeIntel.