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VulnerabilityPublished Updated

CVE-2025-15467: OpenSSL · Out-of-bounds Write

Affects OpenSSLSource CVE Database V5

0
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Public exploit available · CVSS 8.8 High · fixed in 3.6.1 : patch OpenSSL as a priority.

Data as of 10 Nov 2026, 12:51 UTC

CVSS 3.1 base score
8.8High
How severe the flaw is on the 0–10 CVSS scale.

Sources agree

CVSS scores by source
CISA-ADPCVSS 3.18.8
ADP (redhat-SADP)CVSS 3.19.8
CISA SSVC
Exploitation
Proof of concept is public or traded
Automatable
Attackers can reliably automate steps 1–4 of the kill chain
Technical impact
Total control over the software or total information disclosure

CISA SSVC assessment, 2026-03-19.

Patch
Available – fixed in 3.6.1, 3.5.5, 3.4.4 +2
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Exploitation evidence

t = 0 is the CVE’s publication on cve.org

  1. Disclosed: evidence found.

    CVE published 27 Jan 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: evidence found.

    CISA SSVC: proof of concept public

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

Timeline

  1. CVE ID reserved

    by OpenSSL Software Foundation

    , 21 days before disclosure

  2. CVE published

    on cve.org

    , t = 0

  3. CISA SSVC assessment

    proof of concept public

    , 51 days after disclosure

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), CISA SSVC, the Metasploit, Exploit-DB and nuclei-templates index as of 10 Nov 2026.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

ProductAffectedFixed in
OpenSSLOpenSSLAffected
  • >=3.6.0 <3.6.1
Fixed in
  • 3.6.1
OpenSSLOpenSSLAffected
  • >=3.5.0 <3.5.5
Fixed in
  • 3.5.5
OpenSSLOpenSSLAffected
  • >=3.4.0 <3.4.4
Fixed in
  • 3.4.4
OpenSSLOpenSSLAffected
  • >=3.3.0 <3.3.6
Fixed in
  • 3.3.6
OpenSSLOpenSSLAffected
  • >=3.0.0 <3.0.19
Fixed in
  • 3.0.19

AI-suggested

Fixed versions of OpenSSL are available: 3.6.1, 3.5.5, 3.4.4, 3.3.6, and 3.0.19. Users and administrators should upgrade to these versions to remediate the vulnerability. Red Hat advises that no effective workaround or mitigation other than upgrading is currently available. Systems using OpenSSL 1.1.1 or 1.0.2 are not affected. Applications should avoid parsing untrusted CMS or PKCS#7 content with AEAD ciphers until patched. Because the vulnerability occurs before authentication, relying on cryptographic validation is insufficient as a mitigation.

Description

CVE-2025-15467 is a stack buffer overflow vulnerability in OpenSSL versions 3.0.0 through before 3.0.19, 3.3.0 through before 3.3.6, 3.4.0 through before 3.4.4, 3.5.0 through before 3.5.5, and 3.6.0 through before 3.6.1. It occurs when parsing CMS AuthEnvelopedData or EnvelopedData messages with maliciously crafted AEAD parameters, specifically an oversized Initialization Vector (IV) in ASN.1 parameters copied into a fixed-size stack buffer without length verification. This can cause a stack-based out-of-bounds write before any authentication, potentially leading to denial of service or remote code execution. The vulnerability does not affect OpenSSL 1.1.1 or 1.0.2, nor the FIPS modules 3.0 through 3.6.1. Exploitability depends on platform and mitigations. Red Hat notes that stack protections mitigate code execution risk but denial of service remains possible. Fixed versions are available.

References

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