Hudgens, who came to fame starring in Disney's 2006 hit, "High School Musical," posted an Instagram picture of the love birds' names carved into the rock surrounded by a heart. (The post has since been removed.)
There's just one problem: The carving may be located in the Red Rock Ranger District of the Coconino National Forest, and it's against federal law to damage "any natural feature or other property of the United States," according to a statement issued by Brady Smith, a Coconino National Forest spokesman.
The maximum fine is $5,000 and/or six months in jail.
It's hard for federal officials to catch people in the act, but posting it to Instagram is what may get Hudgens in trouble.
"On Monday, Feb.15, we became aware -- via media and public reports -- of an Instagram posting by Vanessa Hudgens showing a scratching or carving of a heart with two names in it on a rock that allegedly is on the Red Rock Ranger District of the Coconino National Forest," Smith said in the statement.
Smith declined to comment more on the specific incident until the Forest Service Law Enforcement investigation is completed.
"I can say that the issue of people carving their names and other things in rocks in the Sedona and surrounding area is always a challenge we face, and (we) try to inform people about its destructive nature." he said.
"We have found that when one person carves something, it encourages others to carve," Smith said. "Carving of any kind affects the natural beauty of the area."
Even if the feds don't punish her, people are already smacking Hudgens around on social media.
"Many Arizonans work really hard to preserve the land and to keep the state a nice one," Instagram member _jamie_jeffries_ posted on Hudgen's Instagram account. "Plus it's just rude to go to someone's home and vandalize it. Just disrespectful to those of us who actually value our state."
"What moron would graffiti on Sedona's red rocks?! I hope Vanessa Hudgens is punished for carving on one of the most spectacular places in AZ," posted Meghan McCain, daughter of Sen. John McCain.
Hudgens' Instagram post is gone, but Phoenix-based KSAZ-TV Web Producer Brent Corrado took a screen grab before it was removed.
Fans can still enjoy other posts from Hudgens' trip to Arizona that are still up.