Heap-based buffer overflow in OpenSSL - CVE-2026-31789

Vulnerability identifier: #VU125568

CSH Severity: Medium

CVSS v4: 5.9 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-31789

CWE-ID: CWE-122

Exploitation vector: Remote access

Exploit availability: No public exploit available

The vulnerability allows a remote attacker to execute arbitrary code.

The vulnerability exists due to heap-based buffer overflow in hexadecimal conversion when converting an excessively large OCTET STRING value from an untrusted X.509 certificate to a hexadecimal string on 32-bit platforms. A remote attacker can supply a crafted X.509 certificate to execute arbitrary code.

Only 32-bit platforms are affected, and exploitation requires printing or logging untrusted X.509 certificates containing an OCTET STRING value larger than 1 gigabyte.

OpenSSL
SUSE Linux Enterprise Server 15 SP6
SUSE Linux Enterprise Server 12 SP5
SUSE Linux Enterprise Server 12 SP5 LTSS Extended
SUSE Linux Enterprise Server 15 SP4
SUSE Linux Enterprise Server 15 SP5
Debian Linux
SUSE Linux Enterprise Server 15
SUSE Linux Enterprise Server for SAP Applications 15
SUSE Linux Enterprise High Performance Computing LTSS 15
SUSE Linux Enterprise High Performance Computing ESPOS 15
SUSE Linux Enterprise High Performance Computing 15
SUSE Linux Enterprise Server for SAP Applications 12
SUSE Linux Enterprise Server 12
SUSE Linux Enterprise High Performance Computing 12
SUSE Linux Enterprise Real Time 15
SUSE Linux Enterprise Desktop 15
SUSE Linux Enterprise Micro
SUSE Linux Enterprise Micro for Rancher
IBM i
Ubuntu
Legacy Module
Development Tools Module
Basesystem Module
openSUSE Leap
openEuler
IBM Cloud Pak System
LANTIME Operating System Firmware (LTOS)
IBM MQ for HPE NonStop
Splunk Universal Forwarder
openssl (Ubuntu package)
libopenssl1_0_0
libopenssl1_0_0-hmac-32bit
libopenssl1_0_0-debuginfo-32bit
libopenssl-1_0_0-devel-32bit
libopenssl1_0_0-32bit
openssl-1_0_0-doc
libopenssl1_0_0-debuginfo
libopenssl1_0_0-hmac
openssl-1_0_0-debugsource
libopenssl-1_0_0-devel
openssl-1_0_0
openssl-1_0_0-debuginfo
openssl-1_0_0-cavs-debuginfo
libopenssl1_0_0-steam-debuginfo
openssl-1_0_0-cavs
libopenssl1_0_0-steam
libopenssl10-debuginfo
libopenssl10
libopenssl1_0_0-steam-32bit
libopenssl1_0_0-32bit-debuginfo
libopenssl1_0_0-steam-32bit-debuginfo
libopenssl1_1-hmac
openssl-1_1-debuginfo
openssl-1_1-debugsource
libopenssl-1_1-devel
openssl-1_1
libopenssl1_1
libopenssl1_1-debuginfo
libopenssl-1_1-devel-32bit
libopenssl1_1-hmac-32bit
libopenssl1_1-32bit
libopenssl1_1-debuginfo-32bit
libopenssl1_1-32bit-debuginfo
libopenssl1_1-64bit-debuginfo
libopenssl1_1-hmac-64bit
libopenssl-1_1-devel-64bit
libopenssl1_1-64bit
openssl-1_1-doc
libopenssl3-64bit
openssl-3
openssl-3-debugsource
libopenssl3
openssl-3-debuginfo
libopenssl3-debuginfo
libopenssl-3-devel
libopenssl3-32bit-debuginfo
libopenssl3-32bit
libopenssl-3-devel-32bit
openssl-3-doc
libopenssl-3-devel-64bit
libopenssl3-64bit-debuginfo
openssl-libs
openssl
openssl-help
openssl-perl
openssl-devel
openssl-debugsource
openssl-debuginfo
openssl (Debian package)
libopenssl-3-fips-provider
libopenssl-3-fips-provider-debuginfo
libopenssl-3-fips-provider-32bit-debuginfo
libopenssl-3-fips-provider-32bit
libopenssl-3-fips-provider-64bit-debuginfo
libopenssl-3-fips-provider-64bit
edk2-debugsource
edk2
python3-edk2-devel
edk2-ovmf
edk2-help
edk2-aarch64
edk2-devel
edk2-debuginfo

Install security update from vendor's website.

OpenSSL - addressed in versions 3.0.20, 3.3.7, 3.4.5, 3.5.6, 3.6.2
IBM Cloud Pak System - update to 2.3.5.1
LANTIME Operating System Firmware (LTOS) - update to 7.10.012
IBM MQ for HPE NonStop - update to 8.1.0.40
Splunk Universal Forwarder - addressed in versions 9.4.14, 10.0.9, 10.2.6, 10.4.2
openssl (Ubuntu package) - addressed in versions 1.0.1f-1ubuntu2.27+esm13, 1.0.2g-1ubuntu4.20+esm15, 1.0.2n-1ubuntu5.13+esm4, 1.1.1f-1ubuntu2.24+esm3, 1.1.1-1ubuntu2.1~18.04.23+esm8, 3.0.2-0ubuntu1.23, 3.0.13-0ubuntu3.9, 3.5.3-1ubuntu3.3
libopenssl1_0_0 - addressed in versions 1.0.2p-3.106.1, 1.0.2p-150000.3.105.1
libopenssl1_0_0-hmac-32bit - addressed in versions 1.0.2p-3.106.1, 1.0.2p-150000.3.105.1
libopenssl1_0_0-debuginfo-32bit - update to 1.0.2p-3.106.1
libopenssl-1_0_0-devel-32bit - addressed in versions 1.0.2p-3.106.1, 1.0.2p-150000.3.105.1
libopenssl1_0_0-32bit - addressed in versions 1.0.2p-3.106.1, 1.0.2p-150000.3.105.1
openssl-1_0_0-doc - addressed in versions 1.0.2p-3.106.1, 1.0.2p-150000.3.105.1
libopenssl1_0_0-debuginfo - addressed in versions 1.0.2p-3.106.1, 1.0.2p-150000.3.105.1
libopenssl1_0_0-hmac - addressed in versions 1.0.2p-3.106.1, 1.0.2p-150000.3.105.1
openssl-1_0_0-debugsource - addressed in versions 1.0.2p-3.106.1, 1.0.2p-150000.3.105.1
libopenssl-1_0_0-devel - addressed in versions 1.0.2p-3.106.1, 1.0.2p-150000.3.105.1
openssl-1_0_0 - addressed in versions 1.0.2p-3.106.1, 1.0.2p-150000.3.105.1
openssl-1_0_0-debuginfo - addressed in versions 1.0.2p-3.106.1, 1.0.2p-150000.3.105.1
openssl-1_0_0-cavs-debuginfo - update to 1.0.2p-150000.3.105.1
libopenssl1_0_0-steam-debuginfo - update to 1.0.2p-150000.3.105.1
openssl-1_0_0-cavs - update to 1.0.2p-150000.3.105.1
libopenssl1_0_0-steam - update to 1.0.2p-150000.3.105.1
libopenssl10-debuginfo - update to 1.0.2p-150000.3.105.1
libopenssl10 - update to 1.0.2p-150000.3.105.1
libopenssl1_0_0-steam-32bit - update to 1.0.2p-150000.3.105.1
libopenssl1_0_0-32bit-debuginfo - update to 1.0.2p-150000.3.105.1
libopenssl1_0_0-steam-32bit-debuginfo - update to 1.0.2p-150000.3.105.1
libopenssl1_1-hmac - addressed in versions 1.1.1d-2.125.1, 1.1.1d-150200.11.109.1, 1.1.1l-150400.7.90.1, 1.1.1l-150500.17.51.1
openssl-1_1-debuginfo - addressed in versions 1.1.1d-2.125.1, 1.1.1d-150200.11.109.1, 1.1.1l-150400.7.90.1, 1.1.1l-150500.17.51.1, 1.1.1w-150600.5.26.2, 1.1.1w-150700.11.16.1
openssl-1_1-debugsource - addressed in versions 1.1.1d-2.125.1, 1.1.1d-150200.11.109.1, 1.1.1l-150400.7.90.1, 1.1.1l-150500.17.51.1, 1.1.1w-150600.5.26.2, 1.1.1w-150700.11.16.1
libopenssl-1_1-devel - addressed in versions 1.1.1d-2.125.1, 1.1.1d-150200.11.109.1, 1.1.1l-150400.7.90.1, 1.1.1l-150500.17.51.1, 1.1.1w-150600.5.26.2, 1.1.1w-150700.11.16.1
openssl-1_1 - addressed in versions 1.1.1d-2.125.1, 1.1.1d-150200.11.109.1, 1.1.1l-150400.7.90.1, 1.1.1l-150500.17.51.1, 1.1.1w-150600.5.26.2, 1.1.1w-150700.11.16.1
libopenssl1_1 - addressed in versions 1.1.1d-2.125.1, 1.1.1d-150200.11.109.1, 1.1.1l-150400.7.90.1, 1.1.1l-150500.17.51.1, 1.1.1w-150600.5.26.2, 1.1.1w-150700.11.16.1
libopenssl1_1-debuginfo - addressed in versions 1.1.1d-2.125.1, 1.1.1d-150200.11.109.1, 1.1.1l-150400.7.90.1, 1.1.1l-150500.17.51.1, 1.1.1w-150600.5.26.2, 1.1.1w-150700.11.16.1
libopenssl-1_1-devel-32bit - addressed in versions 1.1.1d-2.125.1, 1.1.1l-150400.7.90.1, 1.1.1l-150500.17.51.1, 1.1.1w-150600.5.26.2
libopenssl1_1-hmac-32bit - addressed in versions 1.1.1d-2.125.1, 1.1.1l-150400.7.90.1, 1.1.1l-150500.17.51.1
libopenssl1_1-32bit - addressed in versions 1.1.1d-2.125.1, 1.1.1l-150400.7.90.1, 1.1.1l-150500.17.51.1, 1.1.1w-150600.5.26.2, 1.1.1w-150700.11.16.1
libopenssl1_1-debuginfo-32bit - update to 1.1.1d-2.125.1
libopenssl1_1-32bit-debuginfo - addressed in versions 1.1.1l-150400.7.90.1, 1.1.1l-150500.17.51.1, 1.1.1w-150600.5.26.2, 1.1.1w-150700.11.16.1
libopenssl1_1-64bit-debuginfo - addressed in versions 1.1.1l-150400.7.90.1, 1.1.1l-150500.17.51.1, 1.1.1w-150600.5.26.2
libopenssl1_1-hmac-64bit - addressed in versions 1.1.1l-150400.7.90.1, 1.1.1l-150500.17.51.1
libopenssl-1_1-devel-64bit - addressed in versions 1.1.1l-150400.7.90.1, 1.1.1l-150500.17.51.1, 1.1.1w-150600.5.26.2
libopenssl1_1-64bit - addressed in versions 1.1.1l-150400.7.90.1, 1.1.1l-150500.17.51.1, 1.1.1w-150600.5.26.2
openssl-1_1-doc - addressed in versions 1.1.1l-150400.7.90.1, 1.1.1l-150500.17.51.1, 1.1.1w-150600.5.26.2
libopenssl3-64bit - addressed in versions 3.0.8-150400.4.81.1, 3.0.8-150500.5.60.1, 3.1.4-150600.5.45.1
openssl-3 - addressed in versions 3.0.8-150400.4.81.1, 3.0.8-150500.5.60.1, 3.1.4-150600.5.45.1, 3.2.3-150700.5.31.1
openssl-3-debugsource - addressed in versions 3.0.8-150400.4.81.1, 3.0.8-150500.5.60.1, 3.1.4-150600.5.45.1, 3.2.3-150700.5.31.1
libopenssl3 - addressed in versions 3.0.8-150400.4.81.1, 3.0.8-150500.5.60.1, 3.1.4-150600.5.45.1, 3.2.3-150700.5.31.1
openssl-3-debuginfo - addressed in versions 3.0.8-150400.4.81.1, 3.0.8-150500.5.60.1, 3.1.4-150600.5.45.1, 3.2.3-150700.5.31.1
libopenssl3-debuginfo - addressed in versions 3.0.8-150400.4.81.1, 3.0.8-150500.5.60.1, 3.1.4-150600.5.45.1, 3.2.3-150700.5.31.1
libopenssl-3-devel - addressed in versions 3.0.8-150400.4.81.1, 3.0.8-150500.5.60.1, 3.1.4-150600.5.45.1, 3.2.3-150700.5.31.1
libopenssl3-32bit-debuginfo - addressed in versions 3.0.8-150400.4.81.1, 3.0.8-150500.5.60.1, 3.1.4-150600.5.45.1, 3.2.3-150700.5.31.1
libopenssl3-32bit - addressed in versions 3.0.8-150400.4.81.1, 3.0.8-150500.5.60.1, 3.1.4-150600.5.45.1, 3.2.3-150700.5.31.1
libopenssl-3-devel-32bit - addressed in versions 3.0.8-150400.4.81.1, 3.0.8-150500.5.60.1, 3.1.4-150600.5.45.1
openssl-3-doc - addressed in versions 3.0.8-150400.4.81.1, 3.0.8-150500.5.60.1, 3.1.4-150600.5.45.1
libopenssl-3-devel-64bit - addressed in versions 3.0.8-150400.4.81.1, 3.0.8-150500.5.60.1, 3.1.4-150600.5.45.1
libopenssl3-64bit-debuginfo - addressed in versions 3.0.8-150400.4.81.1, 3.0.8-150500.5.60.1, 3.1.4-150600.5.45.1
openssl-libs - update to 3.0.12-47
openssl - update to 3.0.12-47
openssl-help - update to 3.0.12-47
openssl-perl - update to 3.0.12-47
openssl-devel - update to 3.0.12-47
openssl-debugsource - update to 3.0.12-47
openssl-debuginfo - update to 3.0.12-47
openssl (Debian package) - addressed in versions 3.0.19-1~deb12u2, 3.5.5-1~deb13u2
libopenssl-3-fips-provider - addressed in versions 3.1.4-150600.5.45.1, 3.2.3-150700.5.31.1
libopenssl-3-fips-provider-debuginfo - addressed in versions 3.1.4-150600.5.45.1, 3.2.3-150700.5.31.1
libopenssl-3-fips-provider-32bit-debuginfo - addressed in versions 3.1.4-150600.5.45.1, 3.2.3-150700.5.31.1
libopenssl-3-fips-provider-32bit - addressed in versions 3.1.4-150600.5.45.1, 3.2.3-150700.5.31.1
libopenssl-3-fips-provider-64bit-debuginfo - update to 3.1.4-150600.5.45.1
libopenssl-3-fips-provider-64bit - update to 3.1.4-150600.5.45.1
edk2-debugsource - addressed in versions 202308-34, 202308-40
edk2 - addressed in versions 202308-34, 202308-40
python3-edk2-devel - addressed in versions 202308-34, 202308-40
edk2-ovmf - addressed in versions 202308-34, 202308-40
edk2-help - addressed in versions 202308-34, 202308-40
edk2-aarch64 - addressed in versions 202308-34, 202308-40
edk2-devel - addressed in versions 202308-34, 202308-40
edk2-debuginfo - addressed in versions 202308-34, 202308-40

• https://openssl-library.org/news/secadv/20260407.txt

• Multiple vulnerabilities in OpenSSL
• Debian update for openssl
• SUSE update for openssl-3
• SUSE update for openssl-3
• SUSE update for openssl-3
• SUSE update for openssl-1_1
• Ubuntu update for openssl
• Ubuntu update for openssl
• SUSE update for openssl-1_1
• SUSE update for openssl-1_0_0
• SUSE update for openssl-1_1
• SUSE update for openssl-1_1
• SUSE update for openssl-1_0_0
• SUSE update for openssl-3
• SUSE update for openssl-1_1
• SUSE update for openssl-1_1
• openEuler 24.03 LTS SP3 update for openssl
• openEuler 24.03 LTS SP1 update for openssl
• openEuler 24.03 LTS update for openssl
• Multiple vulnerabilities in IBM i
• openEuler 24.03 LTS SP1 update for edk2
• openEuler 24.03 LTS SP3 update for edk2
• Multiple vulnerabilities in IBM Cloud Pak System
• Multiple vulnerabilities in IBM MQ for HPE NonStop
• Multiple vulnerabilities in Meinberg LANTIME Operating System Firmware
• Splunk Universal Forwarder update for third-party components