TI-2025-00277 Aliases CVE-2025-0343 GHSA-w8xv-rwgf-4fwh

Swift ASN.1 can be caused to crash when parsing certain BER/DER constructions.

LOW 39CWE-228Published 2025-01-15 · Updated 2025-03-24

Key facts

Attack vector: Network
Privileges required: None
User interaction: None
Attack complexity: Low
Impact type: —
Confidentiality · integrity · availability: None · None · High
Fix status: Fixed

Attack profile from CVSS 3.1 · CISA ADP. Fix status from CNA and GitHub.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV

EPSS 0.00345 28th percentileScored 2026-11-07

Fix Fixed Swift ASN1 (Swift Project): 1.3.1github.com/apple/swift-asn1 (SwiftURL): 1.3.1

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: None
Automatable: Yes
Technical impact: Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
Apple	Swift ASN1	1.0.0 to before 1.3.1	1.3.1	Patch available	CNA
—	github.com/apple/swift-asn1 (SwiftURL)	before 1.3.1	1.3.1	Patch available	GHSA-w8xv-rwgf-4fwh

Swift ASN1 VendorApple Affected 1.0.0 to before 1.3.1 Fixed in 1.3.1 Patch available CNA
github.com/apple/swift-asn1 (SwiftURL) Vendor— Affected before 1.3.1 Fixed in 1.3.1 Patch available GHSA-w8xv-rwgf-4fwh

Remediation

Fix · CNA Swift ASN1 (Swift Project) Fixed in 1.3.1
Fix · GHSA-w8xv-rwgf-4fwh github.com/apple/swift-asn1 (SwiftURL) Fixed in 1.3.1 Advisory →

Timeline

2026-10-02 Threatist record created from CVE-2025-0343
2026-10-03 Alias added: GHSA-w8xv-rwgf-4fwh

References

Advisory 1

https://nvd.nist.gov/vuln/detail/CVE-2025-0343

Other 3

TI-2026-46583 Improper authentication in Apple macOS KEVCVSS 3.1CRITICAL 9.8
TI-2025-28008 Out-of-bounds write in Apple iOS and iPadOS KEVCVSS 3.1CRITICAL 10.0
TI-2025-22441 Apple iOS and iPadOS: An attacker with arbitrary read and write capability may be able to… KEVCVSS 3.1CRITICAL 9.8
TI-2025-22440 Memory corruption in Apple iOS and iPadOS KEVCVSS 3.1CRITICAL 9.8
TI-2025-17951 Out-of-bounds write in Apple Safari KEVCVSS 3.1CRITICAL 10.0
TI-2025-17847 Use after free in Apple iOS and iPadOS KEVCVSS 3.1CRITICAL 10.0

See all 9536 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences