CVE-2025-0343Network attack vector

Application crash via malformed constructed ASN.1 encoding

Published Jan 15, 2025 · Updated Mar 24, 2025

Improper ASN.1 parsing in Swift Project Swift ASN.1 before 1.3.1 allows remote attackers to crash consuming applications with malformed BER/DER data. The early node parser accepts primitive or constructed encodings that later type decoders treat as impossible and pass to preconditionFailure instead of returning a parsing error. Exploitation requires an application to parse attacker-controlled ASN.1 data; the result is a graceful runtime crash without memory corruption.

CVSS severity7.5
High
EPSS probability0.33%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper ASN.1 parsing in Swift Project Swift ASN.1 before 1.3.1 allows remote attackers to crash consuming applications with malformed BER/DER data. The early node parser accepts primitive or constructed encodings that later type decoders treat as impossible and pass to preconditionFailure instead of returning a parsing error. Exploitation requires an application to parse attacker-controlled ASN.1 data; the result is a graceful runtime crash without memory corruption.

The record

CVE
CVE-2025-0343
Published
Jan 15, 2025
Updated
Mar 24, 2025
Vendor
Swift Project
Product
Swift ASN.1
Classifications
CWE-228, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 15, 2025CVE publishedPublication date reported by the CVE source.
  2. Mar 24, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=1.0.0 <1.3.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Swift Project · Swift ASN.1version=1.0.0 <1.3.1

Published CVSS scores

7.5CISA ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-228Improper Handling of Syntactically Invalid Structure
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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