True, but extremely rare, and like most vaccine side effects, much more common following INFECTION than vaccination.
Association of Cerebral Venous Thrombosis with mRNA COVID-19 Vaccines: A Disproportionality Analysis of the World Health Organization Pharmacovigilance Database
This paper finds that there is an association between vaccination and CVT
"the incidence rate ratio of CVT requiring hospitalization within 6 weeks of SARS-CoV-2 infection was 32 times higher compared with after mRNA-based SARS-CoV-2 vaccination."
"The incidence of CVT and PVT is significantly increased after COVID-19 [compared to after vaccination]. The data highlight the risk of serious thrombotic events in COVID-19 and can help contextualize the risks and benefits of vaccination in this regard."
"COVID-19 increasesthe risk of CVT and PVT compared to patients diagnosed with influenza,andto people who have received aCOVID-19 mRNA vaccine."
"COVID-19 is associated with a markedly increased incidence of CVT compared to patients with influenza, people who have received BNT162b2 or mRNA-1273 vaccines and compared to the best estimates of the general population incidence."