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Fencer Intel
medium 5.3

CVE-2026-22796 json

ASN1_TYPE Type Confusion in the PKCS7_digest_from_attributes() function

published 9mo ago modified 25d ago also EUVD-2026-4813 , GHSA-r9hf-rxjm-gv2f , JLSEC-2026-270

cvss
5.3
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.6%
EPSS 0.6% chance of exploitation in 30 days, percentile 48%
public exploits
0
none known

Summary

Issue summary: A type confusion vulnerability exists in the signature verification of signed PKCS#7 data where an ASN1_TYPE union member is accessed without first validating the type, causing an invalid or NULL pointer dereference when processing malformed PKCS#7 data.

Impact summary: An application performing signature verification of PKCS#7 data or calling directly the PKCS7_digest_from_attributes() function can be caused to dereference an invalid or NULL pointer when reading, resulting in a Denial of Service.

The function PKCS7_digest_from_attributes() accesses the message digest attribute value without validating its type. When the type is not V_ASN1_OCTET_STRING, this results in accessing invalid memory through the ASN1_TYPE union, causing a crash.

Exploiting this vulnerability requires an attacker to provide a malformed signed PKCS#7 to an application that verifies it. The impact of the exploit is just a Denial of Service, the PKCS7 API is legacy and applications should be using the CMS API instead. For these reasons the issue was assessed as Low severity.

The FIPS modules in 3.5, 3.4, 3.3 and 3.0 are not affected by this issue, as the PKCS#7 parsing implementation is outside the OpenSSL FIPS module boundary.

OpenSSL 3.6, 3.5, 3.4, 3.3, 3.0, 1.1.1 and 1.0.2 are vulnerable to this issue.

Patch / fix

  • julia OpenSSL_jll 3.0.20+0, 3.5.5+0
  • julia Openresty_jll 1.29.203+0
  • OpenSSL OpenSSL 1.0.2zn, 1.1.1ze, 3.0.19, 3.3.6, 3.4.4, 3.5.5, 3.6.1
  • openssl Debian 12 3.0.18-1~deb12u2
  • openssl Debian 13 3.5.4-1~deb13u2
  • openssl Debian 14 3.5.5-1

debian advisories DEBIAN-CVE-2026-22796

  • openssl Ubuntu 22.04 LTS 3.0.2-0ubuntu1.21
  • openssl Ubuntu 24.04 LTS 3.0.13-0ubuntu3.7
  • openssl Ubuntu 25.10 3.5.3-1ubuntu3
  • openssl Ubuntu 26.04 LTS 3.5.5-1ubuntu1
  • openssl Ubuntu Pro 14.04 LTS 1.0.1f-1ubuntu2.27+esm12
  • openssl Ubuntu Pro 16.04 LTS 1.0.2g-1ubuntu4.20+esm14
  • openssl Ubuntu Pro FIPS-updates 16.04 LTS 1.0.2g-1ubuntu4.fips.4.20.14
  • openssl Ubuntu Pro 18.04 LTS 1.1.1-1ubuntu2.1~18.04.23+esm7

ubuntu advisories UBUNTU-CVE-2026-22796

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • openssl hummingbird 1 3.5.6-0.1.hum1
  • openssl-libs hummingbird 1 3.5.6-0.1.hum1
  • openssl-perl hummingbird 1 3.5.6-0.1.hum1
  • openssl-config-fips hummingbird 1 3.5.6-0.1.hum1
  • openssl-devel-engine hummingbird 1 3.5.6-0.1.hum1
  • openssl RHEL 9 1:3.5.1-7.el9_7
  • openssl-libs RHEL 9 1:3.5.1-7.el9_7
  • openssl-perl RHEL 9 1:3.5.1-7.el9_7

red hat advisories RHSA-2026:7261RHSA-2026:1473RHSA-2026:1472

  • openssl-3 Linux Micro 6.1 3.1.4-slfo.1.1_8.1
  • openssl-3 Linux Micro 6.0 3.1.4-11.1
  • openssl-3 SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 3.5.0-160000.5.1
  • openssl-1_1 SLES for SAP 15 SP4, SLES 15 SP4-LTSS, SLE Micro 5.4 +3 more 1.1.1l-150400.7.87.1
  • openssl-1_1 SLES for SAP 15 SP5, SLES 15 SP5-LTSS, SLE Micro 5.5 +2 more 1.1.1l-150500.17.46.1
  • openssl-1_1 SLES for SAP 15 SP6, SLES 15 SP6-LTSS, openSUSE Leap 15.6 1.1.1w-150600.5.21.1
  • openssl-1_1 SLE Micro 5.2 1.1.1d-150200.11.106.1
  • openssl-1_0_0 SLES for SAP 15 SP6, SLES for SAP 15 SP5, SLES for SAP 15 SP4 +7 more 1.0.2p-150000.3.102.1

suse advisories SUSE-SU-2026:20373-1SUSE-SU-2026:0498-1SUSE-SU-2026:20349-1SUSE-SU-2026:20211-1SUSE-SU-2026:20223-1SUSE-SU-2026:0360-1

  • openssl-3 openSUSE Leap 16.0 3.5.0-160000.5.1

opensuse advisories openSUSE-SU-2026:20152-1

  • openssl AlmaLinux 10 1:3.5.1-7.el10_1.alma.1
  • openssl-libs AlmaLinux 10 1:3.5.1-7.el10_1.alma.1
  • openssl-perl AlmaLinux 10 1:3.5.1-7.el10_1.alma.1
  • openssl AlmaLinux 9 1:3.5.1-7.el9_7
  • openssl-libs AlmaLinux 9 1:3.5.1-7.el9_7
  • openssl-perl AlmaLinux 9 1:3.5.1-7.el9_7

almalinux advisories ALSA-2026:1472ALSA-2026:1473

  • openssl Rocky Linux 10 1:3.5.1-7.el10_1
  • openssl Rocky Linux 9 1:3.5.1-7.el9_7

rocky linux advisories RLSA-2026:1472RLSA-2026:1473

  • openssl Alpine 3.17 3.0.19-r0
  • openssl Alpine 3.21, Alpine 3.20 3.3.6-r0
  • openssl Alpine 3.24, Alpine 3.23, Alpine 3.22 3.5.5-r0

alpine advisories ALPINE-CVE-2026-22796

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • openssl Azure Linux 3.0 3.3.5-3
  • edk2 Azure Linux 3.0 20240524git3e722403cd16-14
  • edk2 CBL-Mariner 2.0 20230301gitf80f052277c8-47
  • hvloader CBL-Mariner 2.0 1.0.1-18

azure linux advisories AZL-75299AZL-75905AZL-76110AZL-76161

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

Is CVE-2026-22796 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

Check with Fencer

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-22796 updated cvss 5.9

openssl: OpenSSL: Denial of Service via type confusion in PKCS#7 signature verification

  • Red Hat Enterprise Linux 6 openssl, openssl-perl Red Hat Enterprise Linux 7 ovmf, OVMF, AAVMF, openssl, openssl-libs, openssl-perl Red Hat Enterprise Linux 8 edk2, shim, openssl, shim-x64, edk2-ovmf, shim-aa64, +9 more Red Hat Enterprise Linux 9 edk2, shim, shim-x64, edk2-ovmf, shim-aa64, edk2-tools, +4 more Red Hat Enterprise Linux 10 edk2, shim, shim-unsigned-x64, shim-unsigned-aarch64 Red Hat JBoss Core Services openssl
    +1 more products
    Red Hat OpenShift Container Platform 4 openshift/ose-rhel-coreos-8, openshift/ose-rhel-coreos-9
    affected: workaround, no fix available “Fix deferred”
  • Red Hat Cert Manager support for Red Hat OpenShift release 1.18 cert-manager/cert-manager-operator-rhel9 1789029076, cert-manager/jetstack-cert-manager-rhel9 1791459711, cert-manager/cert-manager-istio-csr-rhel9 1791459759, cert-manager/cert-manager-operator-bundle 1791966259, cert-manager/jetstack-cert-manager-acmesolver-rhel9 1791459707
    fixed: vendor fix RHSA-2026:82354
  • Red Hat Cost Management 4 costmanagement 1770836349
    fixed: vendor fix RHSA-2026:3228
  • Red Hat Discovery 2 discovery 1769104765, discovery 1769111774
    fixed: vendor fix RHSA-2026:1736
  • Red Hat Enterprise Linux AppStream (v. 9) openssl-perl 3.5.1-7.el9_7
    fixed: vendor fix RHSA-2026:1473
  • Red Hat Enterprise Linux AppStream (v. 10) openssl-perl 3.5.1-7.el10_1
    fixed: vendor fix RHSA-2026:1472
  • Red Hat Enterprise Linux BaseOS (v. 9) openssl 3.5.1-7.el9_7, openssl-libs 3.5.1-7.el9_7
    fixed: vendor fix RHSA-2026:1473
  • Red Hat Enterprise Linux BaseOS (v. 10) openssl 3.5.1-7.el10_1, openssl-libs 3.5.1-7.el10_1
    fixed: vendor fix RHSA-2026:1472
show 4 more
  • Red Hat Hardened Images openssl 3.5.6-0.1.hum1, openssl-libs 3.5.6-0.1.hum1, openssl-perl 3.5.6-0.1.hum1, openssl-config-fips 3.5.6-0.1.hum1, openssl-devel-engine 3.5.6-0.1.hum1
    fixed: vendor fix RHSA-2026:7261
  • Red Hat Insights proxy 1.5 insights-proxy 1770740405
    fixed: vendor fix RHSA-2026:2485
  • Red Hat Update Infrastructure 5 rhui5 1770646925, rhui5 1773670073, rhui5 1773670137, rhui5 1773672059
    fixed: vendor fix RHSA-2026:4943
  • Red Hat Cost Management 4 costmanagement 1770837277 Red Hat Update Infrastructure 5 rhui5 1770807477, rhui5 1770808689, rhui5 1770808765, rhui5 1773668803
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

cisa ICSA-24-102-01 updated cvss 5.3

Siemens SIMATIC S7-1500 TM MFP

  • Siemens SIMATIC S7-1500 TM MFP - GNU/Linux subsystem
    affected: mitigation, no fix available

Facts from CISA's republication of the vendor's own advisory (CSAF); the linked advisory is the authoritative source. CISA notification · csaf

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
9mo ago

Exploit prediction

0.59% chance of exploitation in the next 30 days, higher than 48% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CISA ADP 3.1 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
CNA 3.1 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
OSV 3.1 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Affected packages

ecosystem package affected fixed in
julia OpenSSL_jll
<3.0.20+0
>=3.5.0+0, <3.5.5+0
3.0.20+0
3.5.5+0
julia Openresty_jll
<1.29.203+0
1.29.203+0

Affected products

  • OpenSSL OpenSSL
  • Siemens SIMATIC S7-1500 TM MFP - GNU/Linux subsystem

Classification

Weakness
  • CWE-754 Improper Check for Unusual or Exceptional Conditions
Technology feeds

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.