Issue summary: Parsing CMS AuthEnvelopedData message with maliciously
crafted AEAD parameters can trigger a stack buffer overflow.

Impact summary: A stack buffer overflow may lead to a crash, causing Denial
of Service, or potentially remote code execution.

When parsing CMS AuthEnvelopedData structures that use AEAD ciphers such as
AES-GCM, the IV (Initialization Vector) encoded in the ASN.1 parameters is
copied into a fixed-size stack buffer without verifying that its length fits
the destination. An attacker can supply a crafted CMS message with an
oversized IV, causing a stack-based out-of-bounds write before any
authentication or tag verification occurs.

Applications and services that parse untrusted CMS or PKCS#7 content using
AEAD ciphers (e.g., S/MIME AuthEnvelopedData with AES-GCM) are vulnerable.
Because the overflow occurs prior to authentication, no valid key material
is required to trigger it. While exploitability to remote code execution
depends on platform and toolchain mitigations, the stack-based write
primitive represents a severe risk.

The FIPS modules in 3.6, 3.5, 3.4, 3.3 and 3.0 are not affected by this
issue, as the CMS implementation is outside the OpenSSL FIPS module
boundary.

OpenSSL 3.6, 3.5, 3.4, 3.3 and 3.0 are vulnerable to this issue.

OpenSSL 1.1.1 and 1.0.2 are not affected by this issue.
Advisories

No advisories yet.

Fixes

Solution

No solution given by the vendor.


Workaround

No workaround given by the vendor.

History

Tue, 27 Jan 2026 16:15:00 +0000

Type Values Removed Values Added
Description Issue summary: Parsing CMS AuthEnvelopedData message with maliciously crafted AEAD parameters can trigger a stack buffer overflow. Impact summary: A stack buffer overflow may lead to a crash, causing Denial of Service, or potentially remote code execution. When parsing CMS AuthEnvelopedData structures that use AEAD ciphers such as AES-GCM, the IV (Initialization Vector) encoded in the ASN.1 parameters is copied into a fixed-size stack buffer without verifying that its length fits the destination. An attacker can supply a crafted CMS message with an oversized IV, causing a stack-based out-of-bounds write before any authentication or tag verification occurs. Applications and services that parse untrusted CMS or PKCS#7 content using AEAD ciphers (e.g., S/MIME AuthEnvelopedData with AES-GCM) are vulnerable. Because the overflow occurs prior to authentication, no valid key material is required to trigger it. While exploitability to remote code execution depends on platform and toolchain mitigations, the stack-based write primitive represents a severe risk. The FIPS modules in 3.6, 3.5, 3.4, 3.3 and 3.0 are not affected by this issue, as the CMS implementation is outside the OpenSSL FIPS module boundary. OpenSSL 3.6, 3.5, 3.4, 3.3 and 3.0 are vulnerable to this issue. OpenSSL 1.1.1 and 1.0.2 are not affected by this issue.
Title Stack buffer overflow in CMS AuthEnvelopedData parsing
Weaknesses CWE-787
References

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: openssl

Published:

Updated: 2026-01-27T16:01:19.922Z

Reserved: 2026-01-06T09:26:41.631Z

Link: CVE-2025-15467

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-01-27T16:16:14.257

Modified: 2026-01-27T16:16:14.257

Link: CVE-2025-15467

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses