CVE-2026-9076
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Description
A flaw was found in OpenSSL. When processing attacker-supplied Cryptographic Message Syntax (CMS) data using password-based decryption, an attacker can choose a stream-mode Key Encryption Key (KEK) cipher. This can trigger a heap out-of-bounds read, potentially causing an application crash and leading to a Denial of Service (DoS). This vulnerability does not require password knowledge and can be exploited before authentication.
Statement
This is a Low impact denial of service due to a heap out-of-bounds read in kek_unwrap_key() when processing attacker-supplied CMS data with an attacker-chosen stream-mode KEK cipher. This flaw requires specific memory conditions (input buffer ending at a page boundary with an unmapped following page) to trigger a crash, which is uncommon in typical Red Hat environments. No information disclosure is possible, and FIPS modules are not affected.
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.
Additional Information
- This content is not included.Bugzilla 2481880: openssl: OpenSSL: Denial of Service due to heap out-of-bounds read in CMS password-based decryption
- Content from cwe.mitre.org is not included.CWE-131: Incorrect Calculation of Buffer Size
- FAQ: Frequently asked questions about CVE-2026-9076
- Offline Security Data data is available for integration with other systems. See Offline Security Data API to get started.
External References
Content from www.cve.org is not included.https://www.cve.org/CVERecord?id=CVE-2026-9076
Content from nvd.nist.gov is not included.https://nvd.nist.gov/vuln/detail/CVE-2026-9076
Affected Packages and Issued Red Hat Security Errata
| Products / Services | Components | State | Errata |
|---|---|---|---|
| Red Hat Enterprise Linux 10 | edk2 | Fix deferred | |
| Red Hat Enterprise Linux 10 | shim | Fix deferred | |
| Red Hat Enterprise Linux 10 | shim-unsigned-aarch64 | Fix deferred | |
| Red Hat Enterprise Linux 10 | shim-unsigned-x64 | Fix deferred | |
| Red Hat Enterprise Linux 10 | openssl | Fixed | RHSA-2026:25237 |
| Red Hat Enterprise Linux 6 | openssl | Fix deferred | |
| Red Hat Enterprise Linux 7 | ovmf | Fix deferred | |
| Red Hat Enterprise Linux 8 | compat-openssl10 | Fix deferred | |
| Red Hat Enterprise Linux 8 | edk2 | Fix deferred | |
| Red Hat Enterprise Linux 8 | mingw-openssl | Fix deferred | |
| Red Hat Enterprise Linux 8 | openssl | Fix deferred | |
| Red Hat Enterprise Linux 8 | shim | Fix deferred | |
| Red Hat Enterprise Linux 8 | shim-unsigned-x64 | Fix deferred | |
| Red Hat Enterprise Linux 9 | compat-openssl11 | Fix deferred | |
| Red Hat Enterprise Linux 9 | edk2 | Fix deferred | |
| Red Hat Enterprise Linux 9 | shim | Fix deferred | |
| Red Hat Enterprise Linux 9 | shim-unsigned-aarch64 | Fix deferred | |
| Red Hat Enterprise Linux 9 | shim-unsigned-x64 | Fix deferred | |
| Red Hat Enterprise Linux 9 | openssl | Fixed | RHSA-2026:25239 |
| Red Hat OpenShift Container Platform 4 | rhcos | Fix deferred | |
| Red Hat Update Infrastructure 5 | rhui5/cds-rhel9 | Fixed | RHSA-2026:26319 |
| Red Hat Update Infrastructure 5 | rhui5/haproxy-rhel9 | Fixed | RHSA-2026:26319 |
| Red Hat Update Infrastructure 5 | rhui5/installer-rhel9 | Fixed | RHSA-2026:26319 |
| Red Hat Update Infrastructure 5 | rhui5/rhua-rhel9 | Fixed | RHSA-2026:26319 |
Common Vulnerability Scoring System (CVSS) Score Details
Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authorities (CNA) source for its products and services (see Red Hat classifications ).
| CVSS v3 Score Breakdown | Red Hat | NVD |
|---|---|---|
| CVSS v3 Base Score | 5.9 | |
| Attack Vector | Network | |
| Attack Complexity | High | |
| Privileges Required | None | |
| User Interaction | None | |
| Scope | Unchanged | |
| Confidentiality Impact | None | |
| Integrity Impact | None | |
| Availability Impact | High |
CVSS v3 Vector
Red Hat CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Frequently Asked Questions
Why is Red Hat's CVSS v3 score or Impact different from other vendors?
For more information, see https://access.redhat.com/solutions/762393.
My product is listed as "Under investigation" or "Affected", when will Red Hat release a fix for this vulnerability?
- "Under investigation" doesn't necessarily mean that the product is affected by this vulnerability. It only means that our Analysis Team is still working on determining whether the product is affected and how it is affected.
- "Affected" means that our Analysis Team has determined that this product is affected by this vulnerability and might release a fix to address this in the near future.
What can I do if my product is listed as "Will not fix"?
Available options depend mostly on the Impact of the vulnerability and the current Life Cycle phase of your product. Overall, you have the following options:
- Upgrade to a supported product version that includes a fix for this vulnerability (recommended).
- Apply a mitigation (if one exists).
- Open a This content is not included.support case to request a prioritization of releasing a fix for this vulnerability.
What can I do if my product is listed as "Fix deferred"?
Available options depend mostly on the Impact of the vulnerability and the current Life Cycle phase of your product. Overall, you have the following options:
- Apply a mitigation (if one exists).
- Open a This content is not included.support case to request a prioritization of releasing a fix for this vulnerability.
- Red Hat Engineering focuses on addressing high-priority issues based on their complexity or limited lifecycle support. Therefore, lower-priority issues will not receive immediate fixes.
What is a mitigation?
I have a Red Hat product but it is not in the above list, is it affected?
Why is my security scanner reporting my product as vulnerable to this vulnerability even though my product version is fixed or not affected?
My product is listed as "Out of Support Scope". What does this mean?
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