VulnerabilityPublished 26 Nov 2025Updated 27 Oct 2026

CVE-2025-21729: linux-realtime, linux-realtime-6.8 vulnerabilities

Affects Linux kernelSource GCVE Database

Mentioned vulnerabilities

Not known to be exploited · fixed in 6.8.1-1038.39~22.04.1 : update Linux kernel when convenient.

Data as of 27 Oct 2026, 06:42 UTC

Severity

Unrated

Rated by Threat Radar · No CVSS score from NVD or the CNA

Patch: Available – fixed in 6.8.1-1038.39~22.04.1, 6.8.1-1038.39

Exploitation evidence

Disclosed: evidence found.
CVE published 26 Nov 2025
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-7889-3

What to do

Upgrade the Ubuntu to 6.8.1-1038.39~22.04.1 (linux-realtime-6.8 package) or 6.8.1-1038.39 (linux-realtime package).

Patches and advisories

ubuntu.com/security/notices/USN-7889-3 (opens in a new tab)

Affected software

Product	Affected	Fixed in
Ubuntu Pro Realtime 24.04 LTSlinux-realtime`pkg:deb/ubuntu/linux-realtime?arch=source&distro=realtime/noble`Other threats	Affected <6.8.1-1038.39	Fixed in 6.8.1-1038.39
Ubuntu Pro Realtime 22.04 LTSlinux-realtime-6.8`pkg:deb/ubuntu/linux-realtime-6.8?arch=source&distro=realtime/jammy`Other threats	Affected <6.8.1-1038.39~22.04.1	Fixed in 6.8.1-1038.39~22.04.1

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

Description

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: - Media drivers; - Network drivers; - Netfilter; - TLS protocol; (CVE-2025-21729, CVE-2025-38227, CVE-2025-38616, CVE-2025-38678)

References

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