CVE-2025-15467Public exploitNetwork attack vectorHinoki check available

Code execution or crash via oversized CMS IV

Published Jan 27, 2026 · Updated Jan 27, 2026

Stack buffer overflow in affected OpenSSL 3.x releases allows attackers to crash processes or execute code via crafted CMS input. The CMS AEAD-parameter parser copies an ASN.1 initialization vector into a fixed-size stack buffer without checking its encoded length. Processing untrusted CMS or PKCS#7 content is required, but the write occurs before authentication; the FIPS modules are outside the affected CMS code.

CVSS severity8.8
High
EPSS probability48.21%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Stack buffer overflow in affected OpenSSL 3.x releases allows attackers to crash processes or execute code via crafted CMS input. The CMS AEAD-parameter parser copies an ASN.1 initialization vector into a fixed-size stack buffer without checking its encoded length. Processing untrusted CMS or PKCS#7 content is required, but the write occurs before authentication; the FIPS modules are outside the affected CMS code.

The record

CVE
CVE-2025-15467
Published
Jan 27, 2026
Updated
Jan 27, 2026
Vendor
OpenSSL Project
Product
OpenSSL
Classifications
CWE-120, CWE-787, T1203
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

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=3.0.0 <3.0.19
  2. Affected versionversion=3.3.0 <3.3.6
  3. Affected versionversion=3.4.0 <3.4.4
  4. Affected versionversion=3.5.0 <3.5.5
  5. Affected versionversion=3.6.0 <3.6.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

OpenSSL Project · OpenSSLversion=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

9.8Red HatCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
8.8CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-120Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
CWE-787Out-of-bounds Write
T1203Exploitation for Client Execution

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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