CVE-2026-80848: Linux kernel · xfrm: espintcp: fix UAF during close
Affects Linux kernelSource GCVE Database
Not known to be exploited.
Data as of 26 Oct 2026, 13:47 UTC
Rated by Threat Radar · CVSS not yet scored by NVD
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 9% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Exploitation evidence
Disclosed: evidence found.
CVE published 4 Sep 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
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.
AI-suggested
A fix for this vulnerability has been implemented in the Linux kernel by adding a synchronize_rcu() call in espintcp_close(). Users should apply the official Linux kernel updates that include this fix.
Description
In the Linux kernel, the following vulnerability has been resolved: xfrm: espintcp: fix UAF during close ZDI reported and analyzed a race condition during close for espintcp sockets: espintcp_close() frees emsg->skb via kfree_skb() without holding any socket lock. Concurrently, the xfrm_trans_reinject work queue invokes esp_output_tcp_finish() -> espintcp_push_skb() -> espintcp_push_msgs() -> skb_send_sock_locked(), which reads the same skb as a data source. Fix this by adding a synchronize_rcu() call after resetting sk_prot, since esp_output_tcp_finish() runs under RCU and won't use a socket with sk_prot == &tcp_prot. Simply taking the socket lock in espintcp_close() could lead to leaks, if esp_output_tcp_finish() re-adds an skb in the slot we just freed. After this, the existing barrier() is no longer needed.
References
- nvd.nist.gov/vuln/detail/CVE-2026-80848 (opens in a new tab)
- git.kernel.org/stable/c/24efebecf415ba264adba0f0491cec436463a14f (opens in a new tab)
- git.kernel.org/stable/c/29121c5e6591da527e8e36ddac7120dc527f574d (opens in a new tab)
- git.kernel.org/stable/c/4b31a875693c480c611519faca46216514e3e052 (opens in a new tab)
- git.kernel.org/stable/c/4bc0dfa28dca6fc0084203732695968049c44072 (opens in a new tab)
- git.kernel.org/stable/c/54b41ad14da9a981131ab6e4d3f79321a503ea5d (opens in a new tab)
- git.kernel.org/stable/c/deb232e884877bf10b4ce2580909eedec986c284 (opens in a new tab)
- git.kernel.org/stable/c/eb3bbf29c723fe75c0eb92be14f0ec92971fe272 (opens in a new tab)
- git.kernel.org/stable/c/ed5d9102190c45fc70121c036b0626b740040b75 (opens in a new tab)
- git.kernel.org/stable/c/ff8dd7a932f34409a56e1b91a1219340f17457e9 (opens in a new tab)
- ubuntu.com/security/CVE-2026-80848 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-80848 (opens in a new tab)
- git.kernel.org/linus/deb232e884877bf10b4ce2580909eedec986c284 (opens in a new tab)