CVE-2025-68206: Linux kernel · netfilter: nft_ct: add seqadj extension for natted connections
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 7.5 High · fixed in 6.8.0-1052.55~22.04.1 : patch Linux kernel soon.
Data as of 26 Oct 2026, 13:47 UTC
- EPSS
- 0.7% chance of exploitation in 30 days – higher than 53% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 6.8.0-1052.55~22.04.1, 6.8.0-1059.65~22.04.1, 6.8.0-1054.57~22.04.1 +35
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:HExploitation 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@6.17.0-14.14?arch=source&distro=questingOther threats | Affected
| Fixed in
|
Ubuntu 25.10linux-awspkg:deb/ubuntu/linux-aws@6.17.0-1007.7?arch=source&distro=questingOther threats | Affected
| Fixed in
|
Ubuntu 25.10linux-azurepkg:deb/ubuntu/linux-azure@6.17.0-1008.8?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@6.17.0-1007.7?arch=source&distro=questingOther threats | Affected
| Fixed in
|
Ubuntu 25.10linux-oraclepkg:deb/ubuntu/linux-oracle@6.17.0-1007.7?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 fix has been implemented in the Linux kernel to address this issue. Users should update to the patched Linux kernel versions listed to resolve the vulnerability. Patch status is confirmed by the resolution of the issue in the specified kernel versions. No additional mitigation steps are indicated beyond applying the official fix.
Description
A vulnerability in the Linux kernel's netfilter nft_ct component related to sequence adjustment for NATted FTP connections using PASV/EPSV modes has been resolved. The issue arises because FTP traffic in passive mode requires rewriting packet payloads, affecting TCP sequence and acknowledgment numbers. This can cause FTP NAT changes to malfunction, leading to connection failures such as '421 Service not available'. The problem occurs when the FTP helper is assigned after DNAT setup, which is not handled correctly in affected versions.
References
- ubuntu.com/security/CVE-2025-68206 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2025-68206 (opens in a new tab)
- git.kernel.org/linus/90918e3b6404c2a37837b8f11692471b4c512de2 (opens in a new tab)
- git.kernel.org/stable/c/2b52d89cbbb0dbe3e948d8d9a91e704316dccfe6 (opens in a new tab)
- git.kernel.org/stable/c/90918e3b6404c2a37837b8f11692471b4c512de2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8029-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8030-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8029-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8048-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8029-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-8179-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8184-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8179-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8185-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8179-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-8203-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8204-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8185-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8179-4 (opens in a new tab)
- ubuntu.com/security/notices/USN-8258-1 (opens in a new tab)