CVE-2025-11187Public exploit

Crash via unchecked PBMAC1 parameters

Published Jan 27, 2026 · Updated Jan 27, 2026

Stack buffer overflow in OpenSSL 3.4.0 through 3.4.3, 3.5.0 through 3.5.4, and 3.6.0 allows local users to crash applications. PKCS#12 MAC verification passes an unvalidated, attacker-controlled PBKDF2 key length to derivation into a fixed 64-byte stack buffer and treats the salt as an OCTET STRING without checking its ASN.1 type. Reachability requires a user or application to process a crafted PBMAC1-protected PKCS#12 file; the overflow grants code execution only where platform mitigations do not block exploitation.

CVSS severity6.1
Medium
EPSS probability4.69%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stack buffer overflow in OpenSSL 3.4.0 through 3.4.3, 3.5.0 through 3.5.4, and 3.6.0 allows local users to crash applications. PKCS#12 MAC verification passes an unvalidated, attacker-controlled PBKDF2 key length to derivation into a fixed 64-byte stack buffer and treats the salt as an OCTET STRING without checking its ASN.1 type. Reachability requires a user or application to process a crafted PBMAC1-protected PKCS#12 file; the overflow grants code execution only where platform mitigations do not block exploitation.

The record

CVE
CVE-2025-11187
Published
Jan 27, 2026
Updated
Jan 27, 2026
Vendor
OpenSSL Project
Product
OpenSSL
Classifications
CWE-476, CWE-787, T1203
Attack vector
local
Privileges
authenticated

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=3.4.0 <3.4.4
  2. Affected versionversion=3.5.0 <3.5.5
  3. Affected versionversion=3.6.0 <3.6.1

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

OpenSSL Project · OpenSSLversion=3.4.0 <3.4.4; version=3.5.0 <3.5.5; version=3.6.0 <3.6.1

Published CVSS scores

6.1CISA-ADPCVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:L/I:L/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)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-476NULL Pointer Dereference
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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