PYSEC-2026-1913 
### Impact
Sentry's Slack integration incorrectly records the incoming request body in logs. This request data can contain sensitive information, including the [deprecated Slack verification token](https://api.slack.com/authentication/verifying-requests-from-slack#deprecation). With this verification token, it is possible under specific configurations, an attacker can forge requests and act as the Slack integration.

The request body is leaked in log entries matching `event == "slack.*" && name == "sentry.integrations.slack" && request_data == *`. The deprecated slack verification token, will be found in the `request_data.token` key.

Example event:

```json
{
    "name": "sentry.integrations.slack",
    "level": "info",
    "event": "slack.event.message",  # This could be any of the `slack.*` events
    "request_data": {
      # Other keys are omitted for brevity
      "token": "<MyDeprecatedSlackVerificationToken>",
    }
}
``` 

### Patches
- **SaaS users** do not need to take any action.
- **Self-hosted users** should upgrade to version 24.5.0 or higher, [rotate their Slack verification token](https://api.slack.com/authentication/verifying-requests-from-slack#regenerating), and [use the Slack Signing Secret instead of the verification token](https://develop.sentry.dev/integrations/slack/).
  - If you are only using the `slack.signing-secret` in your self-hosted configuration, then the legacy verification token is not used to verify the webhook payload. It is ignored. 
 
> ⚠️ Sentry's support for validating Slack requests via the legacy verification token will be deprecated in version 24.7.0.


### Workarounds

#### Option 1

Set the `slack.signing-secret` instead of `slack.verification-token`. The [signing secret](https://api.slack.com/authentication/verifying-requests-from-slack#app-management-updates) is Slack's recommended way of authenticating webhooks.

By having `slack.singing-secret` set, Sentry self-hosted will no longer use the verification token for authentication of the webhooks, regardless of whether `slack.verification-token` is set or not.

#### Option 2

The deprecated Slack verification token is leaked in log levels of `INFO` and `ERROR` in the Slack integration. If the self-hosted instance is unable to be upgraded or re-configured to use the `slack.signing-secret`, the logging configuration can be adjusted to not generate logs from the integration. The [default logging configuration can be found in `src/sentry/conf/server.py`](https://github.com/getsentry/sentry/blob/17d2b87e39ccd57e11da4deed62971ff306253d1/src/sentry/conf/server.py#L1307). **Services should be restarted once the configuration change is saved.**

Below you'll find an example of the configuration adjustments necessary to remove the Slack integration logs:
 
```python
# src/sentry/conf/server.py

...
 
LOGGING: LoggingConfig = {
    ...
    handlers: {
        # the line below already exists in the default configuration
        "null": {"class": "logging.NullHandler"},
        ...
    },
    "loggers": {
        "sentry.integrations.slack": {
            "handlers": ["null"],  # route logs to null handler
            "level": "CRITICAL",  # prevent generation of logs a lower levels (ex. ERROR and INFO)
        },
        ...
    },
}
```

### References
- https://github.com/getsentry/sentry/pull/70508
- [Sentry Slack Integration Documentation for Self-Hosted users](https://develop.sentry.dev/integrations/slack/)
- [Documentation on Slack Signing Secrets](https://api.slack.com/authentication/verifying-requests-from-slack#app-management-updates)
- [Slack Deprecation for Verification Tokens](https://api.slack.com/authentication/verifying-requests-from-slack#deprecation)

CVSS v3.1 score: 2