Faulty second-row headrests may not lock in the upright position, increasing the risk of injury to passengers, according to federal safety regulators.

Chrysler has issued a safety recall for one of its most popular Jeep SUV models, because of an issue with headrests. Over 121,300 Jeep vehicles are affected by the recall, according to the National Highway Traffic Safety Administration.

A second-row headrest issue may seem small, but it’s enough to trigger a recall due to noncompliance with federal safety standards.