NULL pointer dereference in OpenSSL - CVE-2026-28388

Vulnerability identifier: #VU125565

CSH Severity: Low

CVSS v4: 6.3 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-28388

CWE-ID: CWE-476

Exploitation vector: Remote access

Exploit availability: No public exploit available

The vulnerability allows a remote attacker to cause a denial of service.

The vulnerability exists due to NULL pointer dereference in delta CRL processing during X.509 certificate verification when processing a malformed delta CRL that contains a Delta CRL Indicator extension but lacks a CRL Number extension. A remote attacker can provide a malformed CRL to cause a denial of service.

Exploitation requires delta CRL processing to be enabled in the verification context and the certificate or base CRL to indicate freshest CRL processing.

OpenSSL
SUSE Linux Enterprise Server 15 SP4
SUSE Linux Enterprise Server 12 SP5
SUSE Linux Enterprise Server 12 SP5 LTSS Extended
SUSE Linux Enterprise Server 15 SP5
SUSE Linux Enterprise Server 15 SP6
Debian Linux
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 15
SUSE Linux Enterprise Server 12
SUSE Linux Enterprise Server for SAP Applications 12
SUSE Linux Enterprise High Performance Computing 12
SUSE Linux Enterprise Real Time 15
SUSE Linux Enterprise Desktop 15
SUSE Linux Enterprise Micro for Rancher
SUSE Linux Enterprise Micro
IBM i
Ubuntu
Legacy Module
Development Tools Module
Basesystem Module
openSUSE Leap
openEuler
Anolis OS
IBM Cloud Pak System
LANTIME Operating System Firmware (LTOS)
IBM MQ for HPE NonStop
Splunk Universal Forwarder
openssl (Ubuntu package)
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
openssl-1_0_0-debuginfo
libopenssl1_0_0
openssl-1_0_0
libopenssl-1_0_0-devel
openssl-1_0_0-debugsource
libopenssl1_0_0-hmac
libopenssl1_0_0-steam-debuginfo
libopenssl1_0_0-steam-32bit-debuginfo
libopenssl1_0_0-32bit-debuginfo
libopenssl1_0_0-steam-32bit
openssl-1_0_0-cavs-debuginfo
openssl-1_0_0-cavs
libopenssl1_0_0-steam
libopenssl10-debuginfo
libopenssl10
libopenssl1_1-debuginfo-32bit
libopenssl1_1-32bit
libopenssl1_1-hmac-32bit
libopenssl-1_1-devel-32bit
libopenssl1_1-hmac
openssl-1_1-debuginfo
openssl-1_1-debugsource
libopenssl-1_1-devel
openssl-1_1
libopenssl1_1
libopenssl1_1-debuginfo
openssl-devel
openssl-debugsource
openssl-debuginfo
openssl
openssl-help
openssl-libs
libopenssl1_1-64bit-debuginfo
libopenssl1_1-hmac-64bit
libopenssl-1_1-devel-64bit
libopenssl1_1-64bit
openssl-1_1-doc
libopenssl1_1-32bit-debuginfo
compat-openssl11-devel
compat-openssl11-libs
compat-openssl11-debugsource
compat-openssl11-debuginfo
compat-openssl11
openssl-perl
libopenssl3-debuginfo
libopenssl3
libopenssl3-64bit
openssl-3-doc
libopenssl-3-devel-32bit
libopenssl3-32bit
libopenssl3-32bit-debuginfo
libopenssl-3-devel
openssl-3-debuginfo
openssl-3-debugsource
openssl-3
libopenssl-3-devel-64bit
libopenssl3-64bit-debuginfo
openssl-doc
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
shim
shim-debuginfo
shim-debugsource
shim-signed
edk2
edk2-debuginfo
edk2-debugsource
edk2-devel
edk2-aarch64
edk2-help
python3-edk2-devel
edk2-ovmf

Install security update from vendor's website.

OpenSSL - addressed in versions 1.0.2zp, 1.1.1zg, 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 9.4.13, 9.4.14, 10.0.8, 10.0.9, 10.2.5, 10.2.6, 10.4.1, 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-hmac-32bit - addressed in versions 1.0.2p-3.106.1, 1.0.2p-3.109.1, 1.0.2p-150000.3.105.1
libopenssl1_0_0-debuginfo-32bit - addressed in versions 1.0.2p-3.106.1, 1.0.2p-3.109.1
libopenssl-1_0_0-devel-32bit - addressed in versions 1.0.2p-3.106.1, 1.0.2p-3.109.1, 1.0.2p-150000.3.105.1
libopenssl1_0_0-32bit - addressed in versions 1.0.2p-3.106.1, 1.0.2p-3.109.1, 1.0.2p-150000.3.105.1
openssl-1_0_0-doc - addressed in versions 1.0.2p-3.106.1, 1.0.2p-3.109.1, 1.0.2p-150000.3.105.1
libopenssl1_0_0-debuginfo - addressed in versions 1.0.2p-3.106.1, 1.0.2p-3.109.1, 1.0.2p-150000.3.105.1, 1.0.2p-150000.3.108.1
openssl-1_0_0-debuginfo - addressed in versions 1.0.2p-3.106.1, 1.0.2p-3.109.1, 1.0.2p-150000.3.105.1, 1.0.2p-150000.3.108.1
libopenssl1_0_0 - addressed in versions 1.0.2p-3.106.1, 1.0.2p-3.109.1, 1.0.2p-150000.3.105.1, 1.0.2p-150000.3.108.1
openssl-1_0_0 - addressed in versions 1.0.2p-3.106.1, 1.0.2p-3.109.1, 1.0.2p-150000.3.105.1, 1.0.2p-150000.3.108.1
libopenssl-1_0_0-devel - addressed in versions 1.0.2p-3.106.1, 1.0.2p-3.109.1, 1.0.2p-150000.3.105.1, 1.0.2p-150000.3.108.1
openssl-1_0_0-debugsource - addressed in versions 1.0.2p-3.106.1, 1.0.2p-3.109.1, 1.0.2p-150000.3.105.1, 1.0.2p-150000.3.108.1
libopenssl1_0_0-hmac - addressed in versions 1.0.2p-3.106.1, 1.0.2p-3.109.1, 1.0.2p-150000.3.105.1, 1.0.2p-150000.3.108.1
libopenssl1_0_0-steam-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_0_0-32bit-debuginfo - update to 1.0.2p-150000.3.105.1
libopenssl1_0_0-steam-32bit - update to 1.0.2p-150000.3.105.1
openssl-1_0_0-cavs-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 - addressed in versions 1.0.2p-150000.3.105.1, 1.0.2p-150000.3.108.1
libopenssl10 - addressed in versions 1.0.2p-150000.3.105.1, 1.0.2p-150000.3.108.1
libopenssl1_1-debuginfo-32bit - update to 1.1.1d-2.125.1
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-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
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 - 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
openssl-devel - addressed in versions 1.1.1f-42, 1.1.1wa-16, 3.0.12-47
openssl-debugsource - addressed in versions 1.1.1f-42, 1.1.1wa-16, 3.0.12-47
openssl-debuginfo - addressed in versions 1.1.1f-42, 1.1.1wa-16, 3.0.12-47
openssl - addressed in versions 1.1.1f-42, 1.1.1wa-16, 3.0.12-47
openssl-help - addressed in versions 1.1.1f-42, 1.1.1wa-16, 3.0.12-47
openssl-libs - addressed in versions 1.1.1f-42, 1.1.1wa-16, 3.0.12-47
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
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
compat-openssl11-devel - update to 1.1.1m-18
compat-openssl11-libs - update to 1.1.1m-18
compat-openssl11-debugsource - update to 1.1.1m-18
compat-openssl11-debuginfo - update to 1.1.1m-18
compat-openssl11 - update to 1.1.1m-18
openssl-perl - addressed in versions 1.1.1wa-16, 3.0.12-47
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
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
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-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-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
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
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
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
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
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
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
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 3.0.12-23
openssl-doc - update to 3.0.12-23
openssl-perl - update to 3.0.12-23
openssl - update to 3.0.12-23
openssl-devel - update to 3.0.12-23
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
shim - addressed in versions 15.6-30, 15.7-26, 15-41
shim-debuginfo - addressed in versions 15.6-30, 15.7-26, 15-41
shim-debugsource - addressed in versions 15.6-30, 15.7-26, 15-41
shim-signed - update to 15.7-26
edk2 - addressed in versions 202002-35, 202011-32, 202308-34, 202308-40
edk2-debuginfo - addressed in versions 202002-35, 202011-32, 202308-34, 202308-40
edk2-debugsource - addressed in versions 202002-35, 202011-32, 202308-34, 202308-40
edk2-devel - addressed in versions 202002-35, 202011-32, 202308-34, 202308-40
edk2-aarch64 - addressed in versions 202002-35, 202011-32, 202308-34, 202308-40
edk2-help - addressed in versions 202002-35, 202011-32, 202308-34, 202308-40
python3-edk2-devel - addressed in versions 202002-35, 202011-32, 202308-34, 202308-40
edk2-ovmf - addressed in versions 202002-35, 202011-32, 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 shim
• openEuler 24.03 LTS SP1 update for shim
• openEuler 24.03 LTS update for shim
• openEuler 22.03 LTS SP4 update for shim
• openEuler 20.03 LTS SP4 update for shim
• openEuler 22.03 LTS SP4 update for openssl
• openEuler 20.03 LTS SP4 update for openssl
• openEuler 24.03 LTS SP3 update for openssl
• openEuler 24.03 LTS SP1 update for openssl
• openEuler 24.03 LTS update for openssl
• Anolis OS update for openssl
• openEuler 24.03 LTS SP3 update for compat-openssl11
• openEuler 24.03 LTS SP1 update for compat-openssl11
• openEuler 24.03 LTS update for compat-openssl11
• Multiple vulnerabilities in IBM i
• openEuler 24.03 LTS SP1 update for edk2
• openEuler 22.03 LTS SP4 update for edk2
• openEuler 20.03 LTS SP4 update for edk2
• openEuler 24.03 LTS SP3 update for edk2
• SUSE update for openssl-1_0_0
• SUSE update for openssl-1_0_0
• Multiple vulnerabilities in IBM Cloud Pak System
• Multiple vulnerabilities in IBM MQ for HPE NonStop
• Splunk Universal Forwarder update for third-party components (July 2026)
• Multiple vulnerabilities in Meinberg LANTIME Operating System Firmware
• Splunk Universal Forwarder update for third-party components