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Message-ID: <bb5b639af06dc7fdc481629c67e07cd8ef00354c.camel@openssl.org>
Date: Wed, 25 Feb 2026 18:50:52 +0100
From: Tomas Mraz <tomas@...nssl.org>
To: oss-security@...ts.openwall.com
Subject: Re: OpenSSL Security Advisory (updated text for CVE-2025-15467)
We have updated the advisory text for CVE-2025-15467 based on findings
by Jan Lübbe (Pengutronix).
Stack buffer overflow in CMS (Auth)EnvelopedData parsing (CVE-2025-15467)
=========================================================================
Severity: High
Issue summary: Parsing CMS AuthEnvelopedData or EnvelopedData 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 (Auth)EnvelopedData 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 (Auth)EnvelopedData 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.
OpenSSL 3.6 users should upgrade to OpenSSL 3.6.1.
OpenSSL 3.5 users should upgrade to OpenSSL 3.5.5.
OpenSSL 3.4 users should upgrade to OpenSSL 3.4.4.
OpenSSL 3.3 users should upgrade to OpenSSL 3.3.6.
OpenSSL 3.0 users should upgrade to OpenSSL 3.0.19.
This issue was reported on 14th December 2025 by Stanislav Fort (Aisle
Research). The fix was developed by Igor Ustinov.
Jan Lübbe (Pengutronix) reported that CMS EnvelopedData message parsing is
also affected on 10th February 2026.
On Tue, 2026-01-27 at 16:48 +0100, Tomas Mraz wrote:
> OpenSSL Security Advisory [27th January 2026]
> =============================================
...
> Stack buffer overflow in CMS AuthEnvelopedData parsing (CVE-2025-
15467)
>
=======================================================================
>
> Severity: High
>
> 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.
>
> OpenSSL 3.6 users should upgrade to OpenSSL 3.6.1.
>
> OpenSSL 3.5 users should upgrade to OpenSSL 3.5.5.
>
> OpenSSL 3.4 users should upgrade to OpenSSL 3.4.4.
>
> OpenSSL 3.3 users should upgrade to OpenSSL 3.3.6.
>
> OpenSSL 3.0 users should upgrade to OpenSSL 3.0.19.
>
> This issue was reported on 14th December 2025 by Stanislav Fort
(Aisle
> Research). The fix was developed by Igor Ustinov.
```
```
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