GHSA-JWCH-W7WH-GQJM
Vulnerability from github – Published: 2026-04-21 19:05 – Updated: 2026-04-21 19:05Summary
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:
- The handler calls
c.GetRawData()to read the HTTP request body. [file:93] - If
GetRawData()fails, the handler sends an HTTP 500 error response, but does not return. [file:93] - The handler then calls
openapi.Deserialize(policyDataSubscription, reqBody, "application/json"). [file:93] - If deserialization fails, the handler sends an HTTP 400 error response, but again does not return. [file:93]
- 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:
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]
{
"affected": [
{
"package": {
"ecosystem": "Go",
"name": "github.com/free5gc/udr"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"last_affected": "1.4.2"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2026-40343"
],
"database_specific": {
"cwe_ids": [
"CWE-754"
],
"github_reviewed": true,
"github_reviewed_at": "2026-04-21T19:05:18Z",
"nvd_published_at": null,
"severity": "MODERATE"
},
"details": "### Summary\nA 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.\n\nThis may allow unintended creation of Policy Data notification subscriptions with invalid, empty, or partially processed input, depending on downstream processor behavior.\n\n### Details\nThe 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]\n\nIn 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]\n\nThe request flow is:\n\n1. The handler calls `c.GetRawData()` to read the HTTP request body. [file:93]\n2. If `GetRawData()` fails, the handler sends an HTTP 500 error response, but **does not return**. [file:93]\n3. The handler then calls `openapi.Deserialize(policyDataSubscription, reqBody, \"application/json\")`. [file:93]\n4. If deserialization fails, the handler sends an HTTP 400 error response, but again **does not return**. [file:93]\n5. Execution continues and the handler still invokes `s.Processor().PolicyDataSubsToNotifyPostProcedure(c,policyDataSubscription)`. [file:93]\n\nAs 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]\n\nThis 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]\n\n### Security Impact\nThis issue affects a write-capable API that creates Policy Data notification subscriptions. [file:93] \nBecause execution continues after body read or parsing failure, the processor may receive an uninitialized, partially initialized, or otherwise unintended `PolicyDataSubscription` object. [file:93]\n\nThe exact runtime impact depends on downstream processor behavior and storage validation. [file:93] \nAt 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]\n\n### Reproduction Status\nThe 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]\n\n### Patch\nThe handler should immediately terminate after sending an error response for body read or deserialization failure. [file:93]\n\nA minimal fix is to add missing `return` statements in `HandlePolicyDataSubsToNotifyPost`:\n\n```go\nreqBody, err := c.GetRawData()\nif err != nil {\n logger.DataRepoLog.Errorf(\"Get Request Body error: %+v\", err)\n pd := openapi.ProblemDetailsSystemFailure(err.Error())\n c.Set(sbi.IN_PB_DETAILS_CTX_STR, pd.Cause)\n c.JSON(http.StatusInternalServerError, pd)\n return\n}\n\nerr = openapi.Deserialize(\u0026policyDataSubscription, reqBody, \"application/json\")\nif err != nil {\n logger.DataRepoLog.Errorf(\"Deserialize Request Body error: %+v\", err)\n pd := util.ProblemDetailsMalformedReqSyntax(err.Error())\n c.Set(sbi.IN_PB_DETAILS_CTX_STR, pd.Cause)\n c.JSON(http.StatusBadRequest, pd)\n return\n}\n```\nAdditionally, the deserialization call should pass a pointer to the destination\nobject so that the parsed body is written into the intended structure. [file:93]\n\n###Details\nThe issue is compounded by the handler\u0027s deserialization call, which passes\n`policyDataSubscription` directly to `openapi.Deserialize(...)` instead of\npassing a pointer to the destination object. This inconsistent usage further\nincreases the risk that request processing continues with an empty, partially\ninitialized, or otherwise unintended subscription object. [file:93]",
"id": "GHSA-jwch-w7wh-gqjm",
"modified": "2026-04-21T19:05:18Z",
"published": "2026-04-21T19:05:18Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/free5gc/free5gc/security/advisories/GHSA-jwch-w7wh-gqjm"
},
{
"type": "PACKAGE",
"url": "https://github.com/free5gc/free5gc"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "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",
"type": "CVSS_V4"
}
],
"summary": "free5GC UDR: Fail-open handling in PolicyDataSubsToNotifyPost allows unintended subscription creation"
}
Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.