CVE-2026-34180
openssl: OpenSSL: Heap buffer over-read in ASN.1 decoding can lead to denial of service or information disclosure.
Severity
LowRed Hat Product Security
CVSS 3.1
Review impact separately from score.
Published · June 9, 2026
Updated · October 21, 2026
Description
A flaw was found in OpenSSL. An integer truncation vulnerability in the ASN.1 decoder can occur when processing a crafted DER-encoded ASN.1 structure with a primitive element exceeding 2 gigabytes. A remote attacker could exploit this to cause a heap buffer over-read. This may lead to an application crash, resulting in a Denial of Service (DoS), or potentially disclose sensitive information by loading memory contents beyond the input buffer. This issue primarily affects 64-bit Unix and Unix-like platforms.
Statement
This Low impact vulnerability in OpenSSL's ASN.1 decoder affects 64-bit Unix-like platforms, where processing a crafted DER-encoded ASN.1 structure exceeding 2 gigabytes can lead to a heap buffer over-read. This may result in application crashes (Denial of Service) or unintended memory exposure. Red Hat products are only affected if they process untrusted, excessively large ASN.1 input using OpenSSL's d2i_* decoding functions.
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 · 5CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:L/I:N/A:H
CWE-190 · Integer Overflow or Wraparound