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CVE-2026-7383

openssl: OpenSSL: Heap buffer overflow due to signed integer overflow in Unicode output sizing

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Severity

Low

Red Hat Product Security

5.5

CVSS 3.1

Review impact separately from score.

Published · June 9, 2026

Updated · October 15, 2026

Description

A flaw was found in OpenSSL. A signed integer overflow vulnerability exists when sizing the destination buffer for Unicode output. This can lead to a heap buffer overflow, which may result in a crash or potentially allow an attacker to execute arbitrary code. Exploitation requires an application to directly call specific functions with a large amount of attacker-controlled input.

Statement

Low impact. This flaw in OpenSSL's ASN1_mbstring_ncopy() function, leading to a heap buffer overflow, is difficult to exploit in typical Red Hat environments. Exploitation requires an application to directly call the vulnerable function with an extremely large, attacker-controlled input (over half a gigabyte), a scenario not present in standard OpenSSL certificate or network protocol handling.

CVSS score applicability

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

Mitigation

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.

CVSS / CWE

CVSS 3.1 · 5.5
CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:L/I:L/A:H

CWE-190 · Integer Overflow or Wraparound