The article examines the current approaches of the Supreme Court of the Russian Federation to the accessoriness of security obligations. It analyzes the legal positions developed in 2026 concerning the effect of invalidation of performance of the principal obligation on the continued existence of a suretyship, the relationship between the amount of the secured claim and the value of the pledged property, the consequences of reducing a contractual penalty in respect of the surety for the liability of the principal debtor, and the extension of the term of a credit obligation without the surety’s consent. The article demonstrates that the accessoriness of security obligations does not entail a complete and symmetrical dependence of the security upon the principal obligation. It is argued that accessoriness as to amount is primarily intended to limit the liability of the security provider and the extent of the creditor’s recovery, while neither precluding a greater scope of liability on the part of the principal debtor nor requiring the value of the pledged property to correspond to the amount of the secured claim. The article concludes that a surety’s obligation possesses a certain degree of autonomy and that it is necessary to distinguish between termination of the security obligation, alteration of the limits of the surety’s liability, and preservation of the security on its original terms.