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HIGH CWE-787

CVE-2025-15467

Stack buffer overflow in CMS (Auth)EnvelopedData parsing

OpenSSL

8.8/ 10
CVSS 3.1
High severity
75%
EPSS exploit odds
Chance of exploitation in the next 30 days
Higher than 99.5% of all CVEs
Not listed
CISA KEV catalog
No confirmed in-the-wild exploitation on CISA's list, but a public proof of concept exists.
Timeline
Published
Jan 27, 2026
Updated
Oct 15, 2026
First covered
Jul 4, 2026
Latest story
4 months ago

Summary

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.

CWE-787Out-of-bounds Write

Attack profile

Attack vectorNetwork
ComplexityLow
PrivilegesNone
User interactionRequired
ScopeUnchanged
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Affected products

  • OpenSSL3.6.0 to before 3.6.13.5.0 to before 3.5.53.4.0 to before 3.4.43.3.0 to before 3.3.6

References

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