CVE-2026-64580: Linux kernel · xfrm6: clear dst.dev on error to avoid double netdev_put in xfrm6_fill_dst()
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 7.8 High · fixed in 6.8.0-147.147 : patch Linux kernel soon.
Data as of 26 Oct 2026, 17:16 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 2% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 6.8.0-147.147, 6.8.0-1067.70, 6.8.0-1071.79 +26
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 5 Aug 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.
What to do
Upgrade to a fixed release listed under Affected software.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.04 LTSlinuxpkg:deb/ubuntu/linux?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-azure-fdepkg:deb/ubuntu/linux-azure-fde?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-gcppkg:deb/ubuntu/linux-gcp?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-gkepkg:deb/ubuntu/linux-gke?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
Description
In the Linux kernel, the following vulnerability has been resolved: xfrm6: clear dst.dev on error to avoid double netdev_put in xfrm6_fill_dst() On the error path where in6_dev_get(dev) returns NULL, xfrm6_fill_dst() releases the device reference with netdev_put() but leaves xdst->u.dst.dev set. dst_destroy() later calls netdev_put(dst->dev) again, so the same net_device reference is released twice, underflowing its refcount (ref_tracker WARNING + "unregister_netdevice: waiting for <dev> to become free"). Clear xdst->u.dst.dev after the netdev_put(), the same way the XFRM device-offload paths xfrm_dev_state_add() and xfrm_dev_policy_add() in net/xfrm/xfrm_device.c NULL ->dev when releasing the reference on error. ref_tracker: reference already released. ref_tracker: allocated in: xfrm6_fill_dst (net/ipv6/xfrm6_policy.c:86) ... udpv6_sendmsg (net/ipv6/udp.c:1696) ... ref_tracker: freed in: xfrm6_fill_dst (net/ipv6/xfrm6_policy.c:90) ... WARNING: lib/ref_tracker.c:322 at ref_tracker_free+0x58b/0x780 dst_destroy (net/core/dst.c:115) rcu_core handle_softirqs ...
References
- ubuntu.com/security/CVE-2026-64580 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-64580 (opens in a new tab)
- git.kernel.org/linus/136992de9bb91871084ae52d172610541c76e4d2 (opens in a new tab)
- git.kernel.org/stable/c/136992de9bb91871084ae52d172610541c76e4d2 (opens in a new tab)
- git.kernel.org/stable/c/43de8a49335e611adb271bbd52e84dfbc11fc185 (opens in a new tab)
- git.kernel.org/stable/c/df6856c2dda9187601d29b5fbd7a81b3b178cedf (opens in a new tab)
- git.kernel.org/stable/c/e078da1b4e11390cff3201c19a9a1fe70c5b934f (opens in a new tab)
- git.kernel.org/stable/c/ff636d7b7cba6dea82ecf580415ea57f2c1a11b6 (opens in a new tab)
- nvd.nist.gov/vuln/detail/CVE-2026-64580 (opens in a new tab)
- msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-64580.json (opens in a new tab)
- support.microsoft.com/lifecycle (opens in a new tab)
- first.org/cvss (opens in a new tab)
- ubuntu.com/security/notices/USN-8888-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8889-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8887-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8886-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8888-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8887-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8887-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-8917-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8918-1 (opens in a new tab)