# RHSA-2026:77634: kernel security update

RHSA-2026:77634, released July 25, 2026, fixes 7 CVEs in kernel (version 6.12.0-55.109.1.el10_0). None of them is reported as exploited. Patch Radar priority: Urgent.

- Web page: https://patchblox.com/security/fix/linux/rhsa-2026-77634
- Platform: Linux
- Released: Jul 25, 2026
- Priority: Urgent (Closes CVE-2026-43186, rated Critical)
- CVEs: 7, exploited: 0, on CISA KEV: 0
- Vendor advisory: https://access.redhat.com/errata/RHSA-2026:77634

## Applies to

| Product | Release | Fixed in |
|---|---|---|
| [kernel](https://patchblox.com/security/data/product/linux/kernel.md) | RHEL 10 | 6.12.0-55.109.1.el10_0 |

## CVEs this fix closes

| CVE | Priority | Title | CVSS | EPSS | Exploitation |
|---|---|---|---:|---:|---|
| [CVE-2026-43186](https://patchblox.com/security/data/cve/CVE-2026-43186.md) | Urgent | linux: In the Linux kernel, the following vulnerability has been resolved:  ipv6: ioam: fix heap buffer overflow in __ioam6_... | 9.8 | 0.0064 |  |
| [CVE-2026-52924](https://patchblox.com/security/data/cve/CVE-2026-52924.md) | High | sctp: purge outqueue on stale COOKIE-ECHO handling | 9.8 | 0.0066 |  |
| [CVE-2026-64007](https://patchblox.com/security/data/cve/CVE-2026-64007.md) | High | kernel: The kernel packages contain the Linux kernel, the core of any Linux operating system.  Security Fix(es):  * kernel: n... | 9.8 | 0.0051 |  |
| [CVE-2026-64383](https://patchblox.com/security/data/cve/CVE-2026-64383.md) | High | smb: client: fix double-free in SMB2_flush() replay | 9.8 | 0.0046 |  |
| [CVE-2026-64386](https://patchblox.com/security/data/cve/CVE-2026-64386.md) | High | smb: client: fix query_info() replay double-free | 9.8 | 0.0046 |  |
| [CVE-2025-40237](https://patchblox.com/security/data/cve/CVE-2025-40237.md) | High | kernel: The kernel packages contain the Linux kernel, the core of any Linux operating system | 7.1 | 0.0022 |  |
| [CVE-2026-45991](https://patchblox.com/security/data/cve/CVE-2026-45991.md) | High | udf: fix partition descriptor append bookkeeping | 7.8 | 0.0018 |  |

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Data as of 2026-11-07T12:40:37Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo