Appellant seeks review of his conviction and sentence for possession of cocaine with the intent to sell. We affirm Appellant’s conviction without further comment, but because we agree with Appellant that the trial court fundamentally erred when it based his sentence on unsubstantiated allegations of misconduct, we reverse Appellant’s sentence and remand for resentenc-ing before a different judge.

[*1018] Appellant was convicted after a jury tidal of possession of cocaine with the intent to sell, a second-degree felony punishable by up to 15 years in prison. His score-sheet reflected a lowest permissible sentence of a non-state prison sanction, but based on Appellant’s “lengthy criminal history of convictions [and] arrests,” the prosecutor requested a five-year prison sentence followed by five years of drug offender probation. Appellant ^[1] requested 24 months of drug offender probation in a “level-two program.”

The trial court sentenced Appellant to 10 years in prison followed by five years of drug offender probation. The court explained its rationale for this longer-than-requested sentence as follows:

The reason I have sentenced him to this sentence is because I believe that he has either been directly or indirectly involved in the threatening of witnesses in the cases against him, both in this case and in the past. And he comes across as being one-type person, and I don’t believe that, out on the street, he’s that person, and I believe 'that he has been a drug dealer for a long, long time, and I believe that he has endangered peoples’ lives while'he was doing that by committing acts of violence or threatening towards them. That’s why I gave him more than you asked for.

(emphasis added). Additionally, at the conclusion of the sentencing hearing, the court stated to the prosecutor: “He has been harassing yóur witnesses,, and I was concerned about that, and I think I needed to make a statement to him. He needs to quit that.”

On appeal, Appellant contends that the trial court committed fundamental error when it based his sentence on unsubstantiated claims that he threatened witnesses in this case and prior cases. We agree.

“A sentence imposed within the statutory limits ... is generally unassailable on appeal.” Martinez v. State, 123 So.3d 701, 703 (Fla. 1st DCA 2013). However, an exception to this general rule exists when the sentence is based on constitutionally impermissible factors, such as unsubstantiated allegations of wrongdoing. Id. (“Taking ‘unsubstantiated allegations of wrongdoing’ as established fact violates due process.” (quoting Reese v. State, 639 So.2d 1067, 1068 (Fla. 4th DCA 1994))); see also Craun v. State, 124 So.3d 1027 (Fla. 2d DCA 2013) (remanding for resen-tencing where trial court specifically relied on speculation that defendant continued co-defendant’s ongoing scheme of defrauding victims); Epprecht v. State, 488 So.2d 129, 131 (Fla. 3d DCA 1986) (holding that speculation that defendant probably committed other crimes was impermissible sentencing consideration). This is because “a sentence based on mere allegation or surmise violates the fundamental constitutional rights of the defendant.” Martinez, 123 So.3d at 704.

At the sentencing hearing, the prosecutor asserted that Appellant had several prior cases in which the charges against him were dropped because the state- could not get "witnesses to testify. ^[2][*1019] The prosecutor implied that Appellant had threatened the witnesses .not to testify in the prior cases, and she argued that this information was “very relevant” because there were witnesses in the present case who were scared to testify because they had been threatened.

Thére was no record evidence of witness threats in this case, ^[3] nor was there any evidence that Appellant was charged with threatening witnesses in the prior cases. However, it is clear from the trial judge’s comments at the sentencing hearing that he accepted as true, and based his sentencing decision on, the prosecutor’s assertions that Appellant threatened witnesses in this case and her implied assertions that he had threatened witnesses in prior cases.

Although it was not necessarily improper for the trial court to consider Appellant’s prior arrests not resulting in convictions at sentencing, ^[4] it was improper for the court to base Appellant’s sentence in whole or in part on uncharged and wholly unsubstantiated allegations of wrongdoing. And because we are unable to say that the trial court would have imposed the same sentence absent consideration of the impermissible factors, we are required to reverse and remand for resentencing before a different judge. See Yisrael v. State, 65 So.3d 1177, 1178 (Fla. 1st DCA 2011), approved by Norvil v. State, 191 So.3d 406 (Fla.2016); MacIntosh v. State, 182 So.3d 888 (Fla. 5th DCA 2016); Mosley v. State,. — So.3d ——, 40 Fla. L. Weekly D2513, 2015 WL 6777209 (Fla. 2d DCA Nov. 6, 2015).

AFFIRMED in part; REVERSED in part; REMANDED for resentencing.