USN-8658-3: Linux kernel vulnerabilities
Several security issues were discovered in the Linux kernel. An attacker could possibly use these to compromise the system. This update corrects flaws in the following subsystems: - Open vSwitch; - SCTP protocol; (CVE-2026-53224, CVE-2026-53246, CVE-2026-64531)
CSIRTS triage
- What
- Multiple security flaws in the Linux kernel Open vSwitch and SCTP protocol subsystems allow local or remote attackers to compromise system integrity.
- Who is affected
- Systems running vulnerable Linux kernel versions with Open vSwitch or SCTP protocol enabled.
- Urgency
- Moderate to high depending on deployment context; no active exploitation reported at present.
- Action
- Apply the USN-8658-3 kernel security update.
AI-assisted analysis generated from the source advisory — verify against the original.
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Details
Original advisory: https://ubuntu.com/security/notices/USN-8658-3
Exploitation outlook
EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.
- Low exploitation riskCVE-2026-532240.52% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 42% of all EPSS-scored CVEs.
- Low exploitation riskCVE-2026-532460.44% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 37% of all EPSS-scored CVEs.
- Low exploitation riskCVE-2026-645310.38% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 31% of all EPSS-scored CVEs.
Referenced CVEs
| CVE | CSIRTS overview | External |
|---|---|---|
| CVE-2026-53224 | coverage & exploitation status | NVD · CVE.org |
| CVE-2026-53246 | coverage & exploitation status | NVD · CVE.org |
| CVE-2026-64531 | coverage & exploitation status | NVD · CVE.org |
Same CVEs, other sources
How other CERTs, PSIRTs and databases cover the vulnerabilities in this advisory.
- unknownUSN-8659-4: Linux kernel (Oracle) vulnerabilityubuntu
- unknownUSN-8643-4: Linux kernel vulnerabilitiesubuntu
- unknownUSN-8659-3: Linux kernel (Azure) vulnerabilityubuntu
- unknownUSN-8658-2: Linux kernel (IBM) vulnerabilitiesubuntu
- lowUSN-8661-2: Linux kernel (Low Latency) vulnerabilitiesubuntu
- unknownUSN-8643-3: Linux kernel (NVIDIA) vulnerabilitiesubuntu
- unknownUSN-8659-2: Linux kernel (HWE) vulnerabilityubuntu
- unknownUSN-8664-1: Linux kernel (NVIDIA BaseOS) vulnerabilitiesubuntu
- unknownUSN-8663-1: Linux kernel (NVIDIA) vulnerabilitiesubuntu
- unknownUSN-8644-2: Linux kernel (GCP) vulnerabilitiesubuntu
- unknownUSN-8661-1: Linux kernel vulnerabilitiesubuntu
- unknownUSN-8660-1: Linux kernel vulnerabilitiesubuntu
More from Ubuntu Security Notices
- unknownUSN-8659-4: Linux kernel (Oracle) vulnerability2026-08-26
- unknownUSN-8666-2: Linux kernel (Azure) vulnerabilities2026-08-25
- unknownUSN-8630-5: Linux kernel (Raspberry Pi) vulnerabilities2026-08-25
- unknownUSN-8643-4: Linux kernel vulnerabilities2026-08-25
- unknownUSN-8659-3: Linux kernel (Azure) vulnerability2026-08-25