CVE-2025-68227: Linux kernel · mptcp: Fix proto fallback detection with BPF
Affects Linux kernelSource GCVE Database
Not known to be exploited · fixed in 5.15.0-1103.110~20.04.1 : update Linux kernel when convenient.
Data as of 26 Oct 2026, 13:47 UTC
Rated by Threat Radar · No CVSS score from NVD or the CNA
- EPSS
- 0.2% chance of exploitation in 30 days – higher than 11% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 5.15.0-1103.110~20.04.1, 5.15.0-1110.119~20.04.1, 5.15.0-1114.123~20.04.1 +71
Exploitation evidence
Disclosed: evidence found.
CVE published 16 Dec 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.
What to do
Upgrade to a fixed release listed under Affected software.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 25.10linuxpkg:deb/ubuntu/linux@6.17.0-19.19?arch=source&distro=questingOther threats | Affected
| Fixed in
|
Ubuntu 25.10linux-awspkg:deb/ubuntu/linux-aws@6.17.0-1009.9?arch=source&distro=questingOther threats | Affected
| Fixed in
|
Ubuntu 25.10linux-azurepkg:deb/ubuntu/linux-azure@6.17.0-1010.10?arch=source&distro=questingOther threats | Affected
| Fixed in
|
Ubuntu 25.10linux-azure-fdepkg:deb/ubuntu/linux-azure-fde@6.17.0-1017.17?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 25.10linux-gcppkg:deb/ubuntu/linux-gcp@6.17.0-1009.9?arch=source&distro=questingOther threats | Affected
| Fixed in
|
Ubuntu 25.10linux-oraclepkg:deb/ubuntu/linux-oracle@6.17.0-1009.9?arch=source&distro=questingOther threats | Affected
| Fixed in
|
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 to affected Linux kernel versions. The issue is fixed by updating to the patched kernel releases as indicated by the vendor. Users should follow the official Ubuntu security notice USN-8094-1 and update their systems accordingly to mitigate this vulnerability.
Description
A vulnerability in the Linux kernel's MPTCP (Multipath TCP) implementation related to proto fallback detection when using BPF sockmap has been fixed. The issue involved incorrect protocol operations assignment due to improper comparison logic in mptcp_stream_accept, which could cause warnings and potentially incorrect socket behavior. This flaw was addressed by changing the comparison method to use sk_family instead of sk_prot. The vulnerability affects certain Linux kernel versions prior to specific patched releases and has been officially fixed.
References
- ubuntu.com/security/CVE-2025-68227 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2025-68227 (opens in a new tab)
- git.kernel.org/linus/c77b3b79a92e3345aa1ee296180d1af4e7031f8f (opens in a new tab)
- git.kernel.org/stable/c/037cc50589643342d69185b663ecf9d26cce91e8 (opens in a new tab)
- git.kernel.org/stable/c/1a0d5c74af9b6ba9ffdf1172de5a1a6df5922a00 (opens in a new tab)
- git.kernel.org/stable/c/344974ea1a3ca30e4920687b0091bda4438cebdb (opens in a new tab)
- git.kernel.org/stable/c/7ee8f015eb47907745e2070184a8ab1e442ac3c4 (opens in a new tab)
- git.kernel.org/stable/c/92c4092fe012ecdfa5fb05d394f1c1d8f91ad81c (opens in a new tab)
- git.kernel.org/stable/c/9b1980b6f23fa30bf12add19f37c7458625099eb (opens in a new tab)
- git.kernel.org/stable/c/c77b3b79a92e3345aa1ee296180d1af4e7031f8f (opens in a new tab)
- ubuntu.com/security/notices/USN-8094-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8095-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8096-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8100-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8095-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8096-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8094-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8095-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-8096-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-8096-4 (opens in a new tab)