VulnerabilityPublished 23 Jul 2026Updated 27 Oct 2026

CVE-2025-21709: linux-fips, linux-lowlatency, linux-lowlatency-hwe-6.8, linux-oracle vulnerabilities

Affects Linux kernelSource GCVE Database

Mentioned vulnerabilities

Not known to be exploited · fixed in 6.8.0-136.136.2~22.04.1 : patch Linux kernel soon.

Data as of 28 Oct 2026, 05:11 UTC

Severity

High

Rated High by Threat Radar's AI analysis · No CVSS score from NVD or the CNA

EPSS: 0.2% chance of exploitation in 30 days – higher than 9% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 6.8.0-136.136.2~22.04.1, 6.8.0-136.136.2, 6.8.0-1058.61 +1

Exploitation evidence

Disclosed: evidence found.
CVE published 23 Jul 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

usn-8574-2

What to do

Upgrade to a fixed release listed under Affected software.

Patches and advisories

ubuntu.com/security/notices/USN-8574-2 (opens in a new tab)

Affected software

Product	Affected	Fixed in
Ubuntu 24.04 LTSlinux-lowlatency`pkg:deb/ubuntu/linux-lowlatency?arch=source&distro=noble`Other threats	Affected <6.8.0-136.136.2	Fixed in 6.8.0-136.136.2
Ubuntu 24.04 LTSlinux-oracle`pkg:deb/ubuntu/linux-oracle?arch=source&distro=noble`Other threats	Affected <6.8.0-1058.61	Fixed in 6.8.0-1058.61
Ubuntu Pro FIPS-updates 24.04 LTSlinux-fips`pkg:deb/ubuntu/linux-fips?arch=source&distro=fips-updates/noble`Other threats	Affected <6.8.0-136.136+fips2	Fixed in 6.8.0-136.136+fips2
Ubuntu 22.04 LTSlinux-lowlatency-hwe-6.8`pkg:deb/ubuntu/linux-lowlatency-hwe-6.8?arch=source&distro=jammy`Other threats	Affected <6.8.0-136.136.2~22.04.1	Fixed in 6.8.0-136.136.2~22.04.1

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

A patch is available and should be applied immediately. The fixed versions include 6.8.0-136.136.2~22.04.1, 6.8.0-136.136.2, 6.8.0-1058.61, and 6.8.0-136.136+fips2. After applying the update, a system reboot is required to complete remediation. Due to ABI changes, third-party kernel modules must be recompiled and reinstalled. Follow the vendor advisory at https://ubuntu.com/security/notices/USN-8574-2 for detailed update instructions.

Description

Multiple security vulnerabilities were discovered in the Linux kernel affecting various AMD processors and numerous kernel subsystems. These include speculative execution data leakage, privilege escalation via operation cache resource isolation flaws, and entropy issues in RDSEED instruction handling. The update addresses these issues across a wide range of architectures and kernel components. Users must apply the provided patches and reboot to mitigate the risks.

Impact

The vulnerabilities allow local attackers to expose sensitive information, escalate privileges, and compromise confidentiality and integrity through flaws in AMD processor speculative execution, cache resource isolation, and entropy generation. The broad range of kernel subsystem fixes addresses potential system compromise vectors. These issues collectively pose significant risks to system security if unpatched.

Summary

This security update addresses several vulnerabilities in the Linux kernel and AMD processors. CVE-2025-54505 involves improper clearing of data in the floating point divider unit during speculative execution on some AMD processors, allowing local attackers to expose sensitive information. CVE-2025-54518 affects AMD Zen 2 processors where shared resources in the operation cache are not properly isolated, potentially enabling local privilege escalation by corrupting higher privilege instructions. CVE-2025-62626 concerns AMD Zen 5 processors with RDSEED instruction entropy handling flaws, possibly allowing attackers to influence random values, leading to confidentiality and integrity loss. Additionally, numerous security flaws across many Linux kernel subsystems and drivers were fixed, potentially exploitable to compromise systems. The update is available for linux-fips, linux-lowlatency, linux-lowlatency-hwe-6.8, and linux-oracle kernels.

References

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