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CVE-2026-28386 Detail

Description

Issue summary: Applications using AES-CFB128 encryption or decryption on systems with AVX-512 and VAES support can trigger an out-of-bounds read of up to 15 bytes when processing partial cipher blocks. Impact summary: This out-of-bounds read may trigger a crash which leads to Denial of Service for an application if the input buffer ends at a memory page boundary and the following page is unmapped. There is no information disclosure as the over-read bytes are not written to output. The vulnerable code path is only reached when processing partial blocks (when a previous call left an incomplete block and the current call provides fewer bytes than needed to complete it). Additionally, the input buffer must be positioned at a page boundary with the following page unmapped. CFB mode is not used in TLS/DTLS protocols, which use CBC, GCM, CCM, or ChaCha20-Poly1305 instead. For these reasons the issue was assessed as Low severity according to our Security Policy. Only x86-64 systems with AVX-512 and VAES instruction support are affected. Other architectures and systems without VAES support use different code paths that are not affected. OpenSSL FIPS module in 3.6 version is affected by this issue.


Metrics

NVD enrichment efforts reference publicly available information to associate vector strings. CVSS information contributed by other sources is also displayed.
CVSS 4.0 Severity and Vector Strings:

NIST CVSS score
NIST: NVD
N/A
NVD assessment not yet provided.

References to Advisories, Solutions, and Tools

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URL Source(s) Tag(s)
https://github.com/openssl/openssl/commit/61f428a2fc6671ede184a19f71e6e495f0689621 OpenSSL Software Foundation
https://openssl-library.org/news/secadv/20260407.txt OpenSSL Software Foundation

Weakness Enumeration

CWE-ID CWE Name Source
CWE-125 Out-of-bounds Read OpenSSL Software Foundation  

Change History

1 change records found show changes

Quick Info

CVE Dictionary Entry:
CVE-2026-28386
NVD Published Date:
04/07/2026
NVD Last Modified:
04/07/2026
Source:
OpenSSL Software Foundation