Out-of-Bounds Read in CMS Password-Based Decryption
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Denial of service
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- Partial Red Hat: 11 fixed, 6 without a fix
Attack profile from CVSS 3.1 · CISA ADP. Fix status from CNA and Red Hat. Impact type from CWE-125 and the CVSS impact.
Summary
Issue summary: When CMS password-based decryption (RFC 3211 / PWRI key unwrap) processes attacker-supplied CMS data, an attacker-chosen stream-mode KEK cipher can trigger a heap out-of-bounds read in kek_unwrap_key(). Impact summary: A heap buffer over-read may trigger a crash which leads to Denial of Service for an application if the input buffer ends at a memory page boundary and the following page is unmapped. There is no information disclosure as the over-read bytes are not revealed to the attacker. The key unwrapping function performs a check-byte test as specified in the RFC that reads 7 bytes from a heap allocation that is based on the wrapped key length from the message. There is a minimum length check based on the block length of the wrapping cipher. However the cipher is selected from an OID carried in the attacker's PWRI keyEncryptionAlgorithm with no requirement that the cipher be a block cipher. When an attacker selects a stream-mode cipher the guard will be ineffective and the allocated buffer containing the unwrapped key can be too small to fit the check-bytes specified in the RFC and a buffer over-read can happen. Applications calling CMS_decrypt() or CMS_decrypt_set1_password() (equivalently openssl cms -decrypt -pwri_password ...) on untrusted CMS data are vulnerable to this issue. No password knowledge is required: the over-read happens during the unwrap attempt before any authentication succeeds. The over-read is limited to a few bytes and is not written to output, so there is no information disclosure. Triggering a crash requires the allocation to border unmapped memory, which is unlikely with the normal allocator. The FIPS modules are not affected by this issue.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- Yes
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| OpenSSL | OpenSSL | 4.0.0 to before 4.0.1; 3.6.0 to before 3.6.3; 3.5.0 to before 3.5.7; 3.4.0 to before 3.4.6; 3.0.0 to before 3.0.21; 1.1.1 to before 1.1.1zh; 1.0.2 to before 1.0.2zq | 4.0.1, 3.6.3, 3.5.7, 3.4.6, 3.0.21, 1.1.1zh, 1.0.2zq | Patch available | CNA |
- OpenSSL VendorOpenSSL Affected 4.0.0 to before 4.0.1; 3.6.0 to before 3.6.3; 3.5.0 to before 3.5.7; 3.4.0 to before 3.4.6; 3.0.0 to before 3.0.21; 1.1.1 to before 1.1.1zh; 1.0.2 to before 1.0.2zq Fixed in 4.0.1, 3.6.3, 3.5.7, 3.4.6, 3.0.21, 1.1.1zh, 1.0.2zq Patch available CNA
CPE configurations NVD · 2
Remediation
- Fix · CNA OpenSSL (OpenSSL) Fixed in 4.0.1, 3.6.3, 3.5.7, 3.4.6, 3.0.21, 1.1.1zh, 1.0.2zq
Red Hat 22 advisories
- RHSA-2026:82888 Released 2026-10-14 · Red Hat rating Importantcert-manager Operator for Red Hat OpenShift 1.17.2
- Cert Manager support for Red Hat OpenShift release 1.17 registry.redhat.io/cert-manager/cert-manager-operator-bundle
- RHSA-2026:82857 Released 2026-10-14 · Red Hat rating Importantcert-manager Operator for Red Hat OpenShift 1.18.2
- Cert Manager support for Red Hat OpenShift release 1.18 registry.redhat.io/cert-manager/cert-manager-operator-bundle
- RHSA-2026:82372 Released 2026-10-13 · Red Hat rating Importantcert-manager Operator for Red Hat OpenShift 1.18.2
- Cert Manager support for Red Hat OpenShift release 1.18 registry.redhat.io/cert-manager/cert-manager-operator-rhel9
Show 19 more Red Hat advisories
- RHSA-2026:82354 Released 2026-10-13 · Red Hat rating Importantcert-manager Operator for Red Hat OpenShift 1.18.2
- Cert Manager support for Red Hat OpenShift release 1.18 registry.redhat.io/cert-manager/cert-manager-istio-csr-rhel9
- RHSA-2026:82347 Released 2026-10-13 · Red Hat rating Importantcert-manager Operator for Red Hat OpenShift 1.18.2
- Cert Manager support for Red Hat OpenShift release 1.18 registry.redhat.io/cert-manager/jetstack-cert-manager-acmesolver-rhel9, registry.redhat.io/cert-manager/jetstack-cert-manager-rhel9
- RHSA-2026:82322 Released 2026-10-13 · Red Hat rating Importantcert-manager Operator for Red Hat OpenShift 1.17.2
- Cert Manager support for Red Hat OpenShift release 1.17 registry.redhat.io/cert-manager/cert-manager-operator-rhel9
- RHSA-2026:82304 Released 2026-10-13 · Red Hat rating Importantcert-manager Operator for Red Hat OpenShift 1.17.2
- Cert Manager support for Red Hat OpenShift release 1.17 registry.redhat.io/cert-manager/jetstack-cert-manager-acmesolver-rhel9, registry.redhat.io/cert-manager/jetstack-cert-manager-rhel9
- RHSA-2026:72502 Released 2026-09-28 · Red Hat rating Importantcert-manager Operator for Red Hat OpenShift 1.20.1
- Cert Manager support for Red Hat OpenShift release 1.20 registry.redhat.io/cert-manager/cert-manager-trust-manager-rhel9
- RHSA-2026:67551 Released 2026-09-15 · Red Hat rating ImportantRed Hat Hardened Images RPMs bug fix and enhancement update
- Red Hat Hardened Images bootupd-0.3.2-1.hum1@aarch64, bootupd-0.3.2-1.hum1@x86_64, rust-bootupd-0.3.2-1.hum1@src
- RHSA-2026:62790 Released 2026-09-02 · Red Hat rating ImportantRed Hat Hardened Images RPMs bug fix and enhancement update
- Red Hat Hardened Images ruby3.4-3.4.10-31.7.hum1@aarch64, ruby3.4-3.4.10-31.7.hum1@src, ruby3.4-3.4.10-31.7.hum1@x86_64 +10
- RHSA-2026:62563 Released 2026-09-02 · Red Hat rating ImportantRed Hat Hardened Images RPMs Security Update
- Red Hat Hardened Images ruby4.0-4.0.6-37.3.hum1@aarch64, ruby4.0-4.0.6-37.3.hum1@src, ruby4.0-4.0.6-37.3.hum1@x86_64 +46
- RHSA-2026:62562 Released 2026-09-02 · Red Hat rating ImportantRed Hat Hardened Images RPMs Security Update
- Red Hat Hardened Images ruby3.3-3.3.10-23.6.hum1@aarch64, ruby3.3-3.3.10-23.6.hum1@src, ruby3.3-3.3.10-23.6.hum1@x86_64 +46
- RHSA-2026:59641 Released 2026-08-25 · Red Hat rating ImportantRed Hat Hardened Images RPMs bug fix and enhancement update
- Red Hat Hardened Images openssl-1:3.5.8-0.1.hum1@aarch64, openssl-1:3.5.8-0.1.hum1@src, openssl-1:3.5.8-0.1.hum1@x86_64 +12
- RHSA-2026:59635 Released 2026-08-25 · Red Hat rating ImportantRed Hat Hardened Images RPMs bug fix and enhancement update
- Red Hat Hardened Images openssl3-1:3.5.8-0.1.hum1@src, openssl3-devel-1:3.5.8-0.1.hum1@aarch64, openssl3-devel-1:3.5.8-0.1.hum1@x86_64 +4
- RHSA-2026:58981 Released 2026-08-24 · Red Hat rating CriticalRed Hat Update Infrastructure 5.3 Technology Preview security update
- Red Hat Update Infrastructure 5 registry.redhat.io/rhui5/cds-kubernetes-tp-rhel9, registry.redhat.io/rhui5/installer-tp-rhel9, registry.redhat.io/rhui5/rhua-tp-rhel9
- RHSA-2026:55543 Released 2026-08-17 · Red Hat rating ImportantRed Hat Hardened Images RPMs bug fix and enhancement update
- Red Hat Hardened Images python-cryptography-50.0.0-1.hum1@src, python3-cryptography-50.0.0-1.hum1@aarch64, python3-cryptography-50.0.0-1.hum1@x86_64
- RHSA-2026:42825 Released 2026-07-21 · Red Hat rating ImportantRed Hat Hardened Images RPMs bug fix and enhancement update
- Red Hat Hardened Images chunkah-0.6.0-3.hum1@aarch64, chunkah-0.6.0-3.hum1@src, chunkah-0.6.0-3.hum1@x86_64
- RHSA-2026:34102 Released 2026-07-01 · Red Hat rating ImportantInsights proxy Container Image
- Red Hat Insights proxy 1.5 registry.redhat.io/insights-proxy/insights-proxy-container-rhel9
- RHSA-2026:29197 Released 2026-06-24 · Red Hat rating ImportantA Subscription Management tool for finding and reporting Red Hat product usage
- Red Hat Discovery 2 registry.redhat.io/discovery/discovery-server-rhel9, registry.redhat.io/discovery/discovery-ui-rhel9
- RHSA-2026:26319 Released 2026-06-16 · Red Hat rating ImportantRed Hat Update Infrastructure 5.2 security update
- Red Hat Update Infrastructure 5 registry.redhat.io/rhui5/cds-rhel9, registry.redhat.io/rhui5/haproxy-rhel9, registry.redhat.io/rhui5/installer-rhel9 +1
- RHSA-2026:25239 Released 2026-06-11 · Red Hat rating Importantopenssl security update
- Red Hat Enterprise Linux AppStream (v. 9) openssl-devel-1:3.5.5-4.el9_8, openssl-perl-1:3.5.5-4.el9_8
- Red Hat Enterprise Linux BaseOS (v. 9) openssl-1:3.5.5-4.el9_8, openssl-libs-1:3.5.5-4.el9_8
- RHSA-2026:25237 Released 2026-06-11 · Red Hat rating Importantopenssl security update
- Red Hat Enterprise Linux AppStream (v. 10) openssl-devel-1:3.5.5-4.el10_2, openssl-perl-1:3.5.5-4.el10_2
- Red Hat Enterprise Linux BaseOS (v. 10) openssl-1:3.5.5-4.el10_2, openssl-libs-1:3.5.5-4.el10_2
Fixed in the same release
Records fixed by the same vendor advisory or release, as the CNA lists them.
- Advisory ·
OpenSSL — openssl-library.org/news/secadv/20260609.txt
18 records Highest priority Priority MEDIUM 6 MEDIUM, 12 LOW
Other records, highest priority first
- TI-2026-33226 Heap Use-After-Free in the PKCS7_verify() FunctionPriority MEDIUM 47
- TI-2026-26479 CMS AuthEnvelopedData Processing May Accept Forged MessagesPriority MEDIUM 47
- TI-2026-30987 NULL Pointer Dereference in QUIC Server Initial Packet HandlingPriority MEDIUM 41
Vendor assessments
Red Hat
Red Hat rating: Low. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 10 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 6 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 7 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 8 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 9 | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Container Platform 4 | Affected | No fix yet: Fix deferred |
| Cert Manager support for Red Hat OpenShift release 1.17 | Fixed | RHSA-2026:82304, RHSA-2026:82322, RHSA-2026:82888 |
| Cert Manager support for Red Hat OpenShift release 1.18 | Fixed | RHSA-2026:82347, RHSA-2026:82354, RHSA-2026:82372, RHSA-2026:82857 |
| Cert Manager support for Red Hat OpenShift release 1.20 | Fixed | RHSA-2026:72502 |
| Red Hat Discovery 2 | Fixed | RHSA-2026:29197 |
| Red Hat Enterprise Linux AppStream (v. 10) | Fixed | RHSA-2026:25237 |
| Red Hat Enterprise Linux AppStream (v. 9) | Fixed | RHSA-2026:25239 |
| Red Hat Enterprise Linux BaseOS (v. 10) | Fixed | RHSA-2026:25237 |
| Red Hat Enterprise Linux BaseOS (v. 9) | Fixed | RHSA-2026:25239 |
| Red Hat Hardened Images | Fixed | RHSA-2026:42825, RHSA-2026:55543, RHSA-2026:59635, RHSA-2026:59641, RHSA-2026:62562, RHSA-2026:62563, RHSA-2026:62790, RHSA-2026:67551 |
| Red Hat Insights proxy 1.5 | Fixed | RHSA-2026:34102 |
| Red Hat Update Infrastructure 5 | Fixed | RHSA-2026:26319, RHSA-2026:58981 |
Not affected: 5 products
- Red Hat Hardened Images
- Red Hat JBoss Core Services
- Red Hat JBoss Web Server 6
- Red Hat JBoss Web Server 7
- Red Hat Update Infrastructure 5
Timeline
- 2026-10-02 Threatist record created from CVE-2026-9076
- 2026-10-03 Alias added: GHSA-q98x-73c3-57gj
- 2026-10-14 Fix available: RHSA-2026:82304 · Red Hat
- 2026-10-14 Fix available: RHSA-2026:82322 · Red Hat
- 2026-10-14 Fix available: RHSA-2026:82372 · Red Hat
- 2026-10-14 Fix available: RHSA-2026:82354 · Red Hat
- 2026-10-14 Fix available: RHSA-2026:82347 · Red Hat
- 2026-10-15 Fix available: RHSA-2026:82857 · Red Hat
- 2026-10-15 Fix available: RHSA-2026:82888 · Red Hat
- 2026-10-16 Fix available: Cert Manager support for Red Hat OpenShift release 1.17, Cert Manager support for Red Hat OpenShift release 1.18 · Red Hat
References
More Openssl vulnerabilities
- TI-2022-01915 The c_rehash script allows command injection CVSS 3.1CRITICAL 9.8
- TI-2021-02645 SM2 Decryption Buffer Overflow CVSS 3.1CRITICAL 9.8
- TI-2009-03392 The TLS protocol, and the SSL protocol 3.0 and possibly earlier, as used in Microsoft… CVSS 3.1CRITICAL 9.8
- TI-2022-01176 The c_rehash script allows command injection CVSS 3.1CRITICAL 9.8
- TI-2014-00154 The (1) TLS and (2) DTLS implementations in OpenSSL 1.0.1 before 1.0.1g do not properly… KEVCVSS 3.1HIGH 7.5
- TI-2025-14107 Stack buffer overflow in CMS (Auth)EnvelopedData parsing CVSS 3.1HIGH 8.8
Sources
- CVE-2026-9076 · CVE Program
- CVE-2026-9076 · NVD
- FIRST EPSS
- GHSA-q98x-73c3-57gj · GitHub Advisory Database · CC BY 4.0
- CVE-2026-9076 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences