OpenMetadata is a unified platform for discovery, observability, and governance powered by a central metadata repository, in-depth lineage, and seamless team collaboration. Similarly to the GHSL-2023-250 issue, `AlertUtil::validateExpression` is also called from `EventSubscriptionRepository.prepare()`, which can lead to Remote Code Execution. `prepare()` is called from `EntityRepository.prepareInternal()` which, in turn, gets called from `EntityResource.createOrUpdate()`. Note that, even though there is an authorization check (`authorizer.authorize()`), it gets called after `prepareInternal()` gets called and, therefore, after the SpEL expression has been evaluated. In order to reach this method, an attacker can send a PUT request to `/api/v1/events/subscriptions` which gets handled by `EventSubscriptionResource.createOrUpdateEventSubscription()`. This vulnerability was discovered with the help of CodeQL's Expression language injection (Spring) query. This issue may lead to Remote Code Execution and has been addressed in version 1.2.4. Users are advised to upgrade. There are no known workarounds for this vulnerability. This issue is also tracked as `GHSL-2023-251`.

Affected: Maven: org.open-metadata:openmetadata-service

### SpEL Injection in `PUT /api/v1/events/subscriptions` (`GHSL-2023-251`)

***Please note, only authenticated users have access to PUT / POST APIS for /api/v1/policies. Non authenticated users will not be able to access these APIs to exploit the vulnerability. A user must exist in OpenMetadata and have authenticated themselves to exploit this vulnerability.***

Similarly to the GHSL-2023-250 issue, `AlertUtil::validateExpression` is also called from [`EventSubscriptionRepository.prepare()`](https://github.com/open-metadata/OpenMetadata/blob/b6b337e09a05101506a5faba4b45d370cc3c9fc8/openmetadata-service/src/main/java/org/openmetadata/service/jdbi3/EventSubscriptionRepository.java#L69-L83), which can lead to Remote Code Execution.

```java @Override public void prepare(EventSubscription entity, boolean update) { validateFilterRules(entity); }

private void validateFilterRules(EventSubscription entity) { // Resolve JSON blobs into Rule object and perform schema based validation if (entity.getFilteringRules() != null) { List<EventFilterRule> rules = entity.getFilteringRules().getRules(); // Validate all the expressions in the rule for (EventFilterRule rule : rules) { AlertUtil.validateExpression(rule.getCondition(), Boolean.class); } rules.sort(Comparator.comparing(EventFilterRule::getName)); } } ```

`prepare()` is called from [`EntityRepository.prepareInternal()`](https://github.com/open-metadata/OpenMetadata/blob…