free5GC UDR: Fail-open handling in PolicyDataSubsToNotifyPost allows unintended subscription creation

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 UDR is the user data repository (UDR) for free5GC, an an open-source project for 5th generation (5G) mobile core networks. In versions up to and including 1.4.2, a fail-open request handling flaw in the UDR service causes the `/nudr-dr/v2/policy-data/subs-to-notify` POST handler to continue processing requests even after request body retrieval or deserialization errors. This may allow unintended creation of Policy Data notification subscriptions with invalid, empty, or partially processed input, depending on downstream processor behavior. As of time of publication, a patched version is not available.

Source published

21 Apr 2026 23:47:33 UTC

Source modified

22 Apr 2026 13:12:25 UTC

Observed here

23 Oct 2026 15:48:27 UTC

Source terms

CVE Program Terms of Use

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CVSS 4.0 · 6.9 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:L/SA:N

free5GC UDR is the user data repository (UDR) for free5GC, an an open-source project for 5th generation (5G) mobile core networks. In versions up to and including 1.4.2, a fail-open request handling flaw in the UDR service causes the `/nudr-dr/v2/policy-data/subs-to-notify` POST handler to continue processing requests even after request body retrieval or deserialization errors. This may allow unintended creation of Policy Data notification subscriptions with invalid, empty, or partially processed input, depending on downstream processor behavior. As of time of publication, a patched version is not available.

Source published

Apr 21, 2026, 11:47:33 PM (timezone not stated)

Source modified

Apr 22, 2026, 1:12:25 PM (timezone not stated)

Observed here

1 Nov 2026 06:16:33 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 · 6.9 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:L/SA:N

free5GC UDR is the user data repository (UDR) for free5GC, an an open-source project for 5th generation (5G) mobile core networks. In versions up to and including 1.4.2, a fail-open request handling flaw in the UDR service causes the `/nudr-dr/v2/policy-data/subs-to-notify` POST handler to continue processing requests even after request body retrieval or deserialization errors. This may allow unintended creation of Policy Data notification subscriptions with invalid, empty, or partially processed input, depending on downstream processor behavior. As of time of publication, a patched version is not available.

Source published

22 Apr 2026 00:16:27 UTC

Source modified

26 Oct 2026 22:10:00 UTC

Observed here

27 Oct 2026 10:09:56 UTC

Source terms

NIST NVD usage terms; underlying source attribution retained

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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: 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 · 6.9 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:L/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 · 5.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N

### Summary A fail-open request handling flaw in the UDR service causes the `/nudr-dr/v2/policy-data/subs-to-notify` POST handler to continue processing requests even after request body retrieval or deserialization errors. This may allow unintended creation of Policy Data notification subscriptions with invalid, empty, or partially processed input, depending on downstream processor behavior. ### Details The endpoint `POST /nudr-dr/v2/policy-data/subs-to-notify` is intended to create a Policy Data notification subscription only after the HTTP request body has been successfully read and parsed into a valid `PolicyDataSubscription` object. [file:93] In the free5GC UDR implementation, the function `HandlePolicyDataSubsToNotifyPost` in `NFs/udr/internal/sbi/api_datarepository.go` does not terminate execution after input-processing failures. [file:93] The request flow is: 1. The handler calls `c.GetRawData()` to read the HTTP request body. [file:93] 2. If `GetRawData()` fails, the handler sends an HTTP 500 error response, but **does not return**. [file:93] 3. The handler then calls `openapi.Deserialize(policyDataSubscription, reqBody, "application/json")`. [file:93] 4. If deserialization fails, the handler sends an HTTP 400 error response, but again **does not return**. [file:93] 5. Execution continues and the handler still invokes `s.Processor().PolicyDataSubsToNotifyPostProcedure(c,policyDataSubscription)`. [file:93] As a result, the endpoint operates in a fail-open manner: request processing may continue after fatal input validation or body handling errors, instead of being safely aborted. [file:93] This differs from safer handlers in the same file, which use a helper pattern that explicitly returns on body read or deserialization failure before calling the corresponding processor routine. [file:93] ### Security Impact This issue affects a write-capable API that creates Policy Data notification subscriptions. [file:93] Because execution continues after body read or parsing failure, the processor may receive an uninitialized, partially initialized, or otherwise unintended `PolicyDataSubscription` object. [file:93] The exact runtime impact depends on downstream processor behavior and storage validation. [file:93] At minimum, this is a security-relevant robustness flaw that can lead to inconsistent request handling; under certain runtime conditions it may allow creation of invalid or unintended subscription state. [file:93] ### Reproduction Status The code path has been statically confirmed. [file:93] A complete runtime proof of unintended subscription creation after `GetRawData()` or deserialization failure has not yet been established. [file:93] ### Patch The handler should immediately terminate after sending an error response for body read or deserialization failure. [file:93] A minimal fix is to add missing `return` statements in `HandlePolicyDataSubsToNotifyPost`: ```go reqBody, err := c.GetRawData() if err != nil { logger.DataRepoLog.Errorf("Get Request Body error: %+v", err) pd := openapi.ProblemDetailsSystemFailure(err.Error()) c.Set(sbi.IN_PB_DETAILS_CTX_STR, pd.Cause) c.JSON(http.StatusInternalServerError, pd) return } err = openapi.Deserialize(&policyDataSubscription, reqBody, "application/json") if err != nil { logger.DataRepoLog.Errorf("Deserialize Request Body error: %+v", err) pd := util.ProblemDetailsMalformedReqSyntax(err.Error()) c.Set(sbi.IN_PB_DETAILS_CTX_STR, pd.Cause) c.JSON(http.StatusBadRequest, pd) return } ``` Additionally, the deserialization call should pass a pointer to the destination object so that the parsed body is written into the intended structure. [file:93] ###Details The issue is compounded by the handler's deserialization call, which passes `policyDataSubscription` directly to `openapi.Deserialize(...)` instead of passing a pointer to the destination object. This inconsistent usage further increases the risk that request processing continues with an empty, partially initialized, or otherwise unintended subscription object. [file:93]

Source published

21 Apr 2026 19:05:18 UTC

Source modified

25 Jun 2026 23:11:35 UTC

Observed here

24 Oct 2026 13:19:41 UTC

Source terms

GitHub Advisory Database · CC-BY-4.0

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

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

Publisher rating · MODERATE

free5GC UDR: Fail-open handling in PolicyDataSubsToNotifyPost allows unintended subscription creation in github.com/free5gc/udr

Source published

25 Jun 2026 22:34:31 UTC

Source modified

25 Jun 2026 23:01:15 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.