CVE-2026-80848
xfrm: espintcp: fix UAF during close
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.
INFO
Published Date :
Sept. 4, 2026, 4:18 p.m.
Last Modified :
Sept. 4, 2026, 4:18 p.m.
Remotely Exploit :
No
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Solution
- Update the Linux kernel to the latest patched version.
- Ensure RCU synchronization is properly implemented.
- Review socket lock usage in espintcp_close.
- Remove unnecessary barriers after fixes.
References to Advisories, Solutions, and Tools
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CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
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associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
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stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-80848
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
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Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Sep. 04, 2026
Action Type Old Value New Value Added 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. Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/80xxx/CVE-2026-80848.json">CVE-2026-80848</a> Added Reference https://git.kernel.org/stable/c/24efebecf415ba264adba0f0491cec436463a14f Added Reference https://git.kernel.org/stable/c/29121c5e6591da527e8e36ddac7120dc527f574d Added Reference https://git.kernel.org/stable/c/4b31a875693c480c611519faca46216514e3e052 Added Reference https://git.kernel.org/stable/c/4bc0dfa28dca6fc0084203732695968049c44072 Added Reference https://git.kernel.org/stable/c/54b41ad14da9a981131ab6e4d3f79321a503ea5d Added Reference https://git.kernel.org/stable/c/deb232e884877bf10b4ce2580909eedec986c284 Added Reference https://git.kernel.org/stable/c/eb3bbf29c723fe75c0eb92be14f0ec92971fe272 Added Reference https://git.kernel.org/stable/c/ed5d9102190c45fc70121c036b0626b740040b75 Added Reference https://git.kernel.org/stable/c/ff8dd7a932f34409a56e1b91a1219340f17457e9