CVE-2025-15467 Stack buffer overflow in CMS (Auth)EnvelopedData parsing
Attackers can trigger a stack buffer overflow in OpenSSL by sending crafted CMS messages with oversized IVs, potentially causing crashes or remote code execution.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2025-15467?
CVE-2025-15467 is a high-severity memory corruption vulnerability in Openssl Openssl, published on 27 Jan 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
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.
Which versions are affected by CVE-2025-15467?
It affects 1 product.
Products include Openssl Openssl.
How do I fix CVE-2025-15467?
Apply the vendor's patch.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2025-15467 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-15467 exists.
Public exploit code: 5 proofs of concept on GitHub.
Other vulnerabilities in Openssl Openssl
Sources
Also known as ALPINE-CVE-2025-15467, AZL-75791, AZL-75908, BELL-CVE-2025-15467, CLEANSTART-2026-VU59374, DEBIAN-CVE-2025-15467 and 14 more.