CVE-2026-64566: Linux kernel · xfrm: iptfs: propagate SKBFL_SHARED_FRAG in iptfs_skb_add_frags()
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 9.8 Critical · fixed in 7.0.0-38.38~24.04.4 : patch Linux kernel as a priority.
Data as of 26 Oct 2026, 14:05 UTC
- EPSS
- 0.3% chance of exploitation in 30 days – higher than 28% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 7.0.0-38.38~24.04.4, 7.0.0-38.38, 7.0.0-1014.14 +11
CVSS:3.1/AV:N/AC:L/PR:N/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: xfrm: iptfs: propagate SKBFL_SHARED_FRAG in iptfs_skb_add_frags() When iptfs_skb_add_frags() copies frag references from the source frag walk into a new SKB, it increments the page reference count via __skb_frag_ref() but does not propagate SKBFL_SHARED_FRAG to the destination SKB's skb_shinfo->flags. If the source SKB carries shared frags (e.g. from a page-pool backed receive path), the new inner SKB will appear to ESP as having privately owned frags. A subsequent esp_input() call for a nested transport-mode SA then takes the no-COW fast path and decrypts in place, writing over pages that are still referenced by the outer IPTFS SKB. This causes kernel-visible memory corruption and can trigger a panic. All other frag-transfer helpers in the kernel (skb_try_coalesce, skb_gro_receive, __pskb_copy_fclone, skb_shift, skb_segment) correctly propagate SKBFL_SHARED_FRAG; align iptfs_skb_add_frags() with this convention by setting the flag inside the loop immediately after __skb_frag_ref() and nr_frags++, so every exit path that attaches a frag unconditionally propagates SKBFL_SHARED_FRAG.
References
- ubuntu.com/security/CVE-2026-64566 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-64566 (opens in a new tab)
- git.kernel.org/linus/430ea57d6daf765e88f90046afbfd1e071cb7200 (opens in a new tab)
- git.kernel.org/stable/c/430ea57d6daf765e88f90046afbfd1e071cb7200 (opens in a new tab)
- git.kernel.org/stable/c/d8aaf06b29f5a0b6186cf68d21c7d63678ee3891 (opens in a new tab)
- git.kernel.org/stable/c/ffd64e0717efd83fbf3396ab4e5ac6d795dac4d0 (opens in a new tab)
- nvd.nist.gov/vuln/detail/CVE-2026-64566 (opens in a new tab)
- wid.cert-bund.de/.well-known/csaf/white/2026/wid-sec-w-2026-2659.json (opens in a new tab)
- wid.cert-bund.de/portal/wid/securityadvisory?name=WID-SEC-2026-2659 (opens in a new tab)
- lore.kernel.org/linux-cve-announce/ (opens in a new tab)
- lore.kernel.org/linux-cve-announce/2026080506-CVE-2026-64566-e654@gregkh/ (opens in a new tab)
- lore.kernel.org/linux-cve-announce/2026080558-CVE-2026-64567-a7b8@gregkh/ (opens in a new tab)
- lore.kernel.org/linux-cve-announce/2026080559-CVE-2026-64568-2437@gregkh/ (opens in a new tab)
- lore.kernel.org/linux-cve-announce/2026080559-CVE-2026-64569-3355@gregkh/ (opens in a new tab)
- lore.kernel.org/linux-cve-announce/2026080559-CVE-2026-64570-8771@gregkh/ (opens in a new tab)
- lore.kernel.org/linux-cve-announce/2026080559-CVE-2026-64571-f2f0@gregkh/ (opens in a new tab)
- lore.kernel.org/linux-cve-announce/2026080559-CVE-2026-64572-e260@gregkh/ (opens in a new tab)
- lore.kernel.org/linux-cve-announce/2026080500-CVE-2026-64573-d88e@gregkh/ (opens in a new tab)
- lore.kernel.org/linux-cve-announce/2026080500-CVE-2026-64574-f7a5@gregkh/ (opens in a new tab)
- lore.kernel.org/linux-cve-announce/2026080523-CVE-2026-64575-f476@gregkh/ (opens in a new tab)
- lore.kernel.org/linux-cve-announce/2026080524-CVE-2026-64576-38cf@gregkh/ (opens in a new tab)
- lore.kernel.org/linux-cve-announce/2026080524-CVE-2026-64577-0dfc@gregkh/ (opens in a new tab)
- lore.kernel.org/linux-cve-announce/2026080524-CVE-2026-64578-ebe9@gregkh/ (opens in a new tab)
- lore.kernel.org/linux-cve-announce/2026080524-CVE-2026-64579-e472@gregkh/ (opens in a new tab)
- lore.kernel.org/linux-cve-announce/2026080525-CVE-2026-64580-00ec@gregkh/ (opens in a new tab)
- lore.kernel.org/linux-cve-announce/2026080525-CVE-2026-64581-62bc@gregkh/ (opens in a new tab)
- security-tracker.debian.org/tracker/DSA-6415-1 (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-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)