CVE-2025-0343: swift project swift asn1

Vulnerability summary

CVE-2025-0343 is a high (CVSS 7.5) vulnerability in swift project swift asn1. EPSS estimates a 0.33% chance of exploitation in the next 30 days, higher than 24.8% of scored vulnerabilities.

Timeline

1. 15-01-2025
   PublishedVulnerability first disclosed.
2. 24-03-2025
   Last modifiedVulnerability information updated.

Description

Swift ASN.1 can be caused to crash when parsing certain BER/DER constructions. This crash is caused by a confusion in the ASN.1 library itself which assumes that certain objects can only be provided in either constructed or primitive forms, and will trigger a preconditionFailure if that constraint isn't met. Importantly, these constraints are actually required to be true in DER, but that correctness wasn't enforced on the early node parser side so it was incorrect to rely on it later on in decoding, which is what the library did. These crashes can be triggered when parsing any DER/BER format object. There is no memory-safety issue here: the crash is a graceful one from the Swift runtime. The impact of this is that it can be used as a denial-of-service vector when parsing BER/DER data from unknown sources, e.g. when parsing TLS certificates.

• CWE-228Improper Handling of Syntactically Invalid StructureThe product does not handle or incorrectly handles input that is not syntactically well-formed with respect to the associated specification.