CVE-2025-0343
Swift ASN.1 can be caused to crash when parsing certain BER/DER constructions.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.33%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
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.
- CVSS 3.1
- 7.5 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- EPSS
- 0.33% probability · 26th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-228
- Source
- cve@forums.swift.org
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.