CVE-2025-69420Network attack vector

Application crash via unchecked ASN1_TYPE union access

Published Jan 27, 2026 · Updated Jan 27, 2026

Type confusion in OpenSSL allows attackers to crash timestamp-verifying applications via a malformed TimeStamp Response file. The ossl_ess_get_signing_cert() and ossl_ess_get_signing_cert_v2() functions read the sequence arm of an ASN1_TYPE union without confirming V_ASN1_SEQUENCE. Reachability requires an application to accept an attacker-supplied RFC 3161 response and call TS_RESP_verify_response(); the reported consequence is a process crash without data disclosure or code execution.

CVSS severity7.5
High
EPSS probability0.81%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Type confusion in OpenSSL allows attackers to crash timestamp-verifying applications via a malformed TimeStamp Response file. The ossl_ess_get_signing_cert() and ossl_ess_get_signing_cert_v2() functions read the sequence arm of an ASN1_TYPE union without confirming V_ASN1_SEQUENCE. Reachability requires an application to accept an attacker-supplied RFC 3161 response and call TS_RESP_verify_response(); the reported consequence is a process crash without data disclosure or code execution.

The record

CVE
CVE-2025-69420
Published
Jan 27, 2026
Updated
Jan 27, 2026
Vendor
OpenSSL Project
Product
OpenSSL
Classifications
CWE-754, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 27, 2026CVE publishedPublication date reported by the CVE source.
  2. Jan 27, 2026Record 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=1.1.1 <1.1.1ze
  2. Affected versionversion=3.0.0 <3.0.19
  3. Affected versionversion=3.3.0 <3.3.6
  4. Affected versionversion=3.4.0 <3.4.4
  5. Affected versionversion=3.5.0 <3.5.5
  6. Affected versionversion=3.6.0 <3.6.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

OpenSSL Project · OpenSSLversion=1.1.1 <1.1.1ze; version=3.0.0 <3.0.19; version=3.3.0 <3.3.6; version=3.4.0 <3.4.4; version=3.5.0 <3.5.5; version=3.6.0 <3.6.1

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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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-754Improper Check for Unusual or Exceptional Conditions
T1499Endpoint Denial of Service

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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