Botan is a widely used C++ cryptography library. In versions earlier than 3.12.0, the parser accepted certain indefinite length encodings in BER data, even within structures that must be DER encoded. This misuse caused the parser to exhibit quadratic time complexity, meaning an attacker could craft BER input that would make the library consume excessive CPU and memory, leading to service interruption. The weakness is classified as CWE‑407, reflecting an inefficient algorithm that degrades performance.

The affected product is the Botan library from the vendor randombit. All releases prior to 3.12.0 are vulnerable. Systems that integrate Botan for cryptographic operations—such as application servers, network devices, or any software that processes ASN.1 data—could be impacted if they use these older versions.

The CVSS score of 6.9 indicates a moderate severity. Although the EPSS score is unavailable, the vulnerability is exploit‑ready: an attacker only needs to supply the crafted BER input to the library, which is often impractical to do through a network interface unless the application exposes a parsing endpoint. The vulnerability is not listed in CISA's KEV, but the potential for a denial‑of‑service attack remains because the library degrades gracefully to a high CPU state rather than crashing. Consequently, the risk is significant for services that rely heavily on Botan for data processing and cannot tolerate outages.