https://cve.radiocsirt.org/rss/recent/all/10 Most recent entries from all 2026-10-05T09:33:36.738623+00:00 Vulnerability-Lookup csirt@opendfir.org python-feedgen Contains only the most 10 recent entries. https://cve.radiocsirt.org/vuln/cve-2025-39955 CVE-2025-39955 — tcp: Clear tcp_sk(sk)->fastopen_rsk in tcp_disconnect(). 2026-10-05T09:33:36.981411+00:00

Affected: Linux, Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP, Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP, Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP

In the Linux kernel, the following vulnerability has been resolved:

tcp: Clear tcp_sk(sk)->fastopen_rsk in tcp_disconnect().

syzbot reported the splat below where a socket had tcp_sk(sk)->fastopen_rsk in the TCP_ESTABLISHED state. [0]

syzbot reused the server-side TCP Fast Open socket as a new client before the TFO socket completes 3WHS:

1. accept() 2. connect(AF_UNSPEC) 3. connect() to another destination

As of accept(), sk->sk_state is TCP_SYN_RECV, and tcp_disconnect() changes it to TCP_CLOSE and makes connect() possible, which restarts timers.

Since tcp_disconnect() forgot to clear tcp_sk(sk)->fastopen_rsk, the retransmit timer triggered the warning and the intended packet was not retransmitted.

Let's call reqsk_fastopen_remove() in tcp_disconnect().

[0]: WARNING: CPU: 2 PID: 0 at net/ipv4/tcp_timer.c:542 tcp_retransmit_timer (net/ipv4/tcp_timer.c:542 (discriminator 7)) Modules linked in: CPU: 2 UID: 0 PID: 0 Comm: swapper/2 Not tainted 6.17.0-rc5-g201825fb4278 #62 PREEMPT(voluntary) Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 RIP: 0010:tcp_retransmit_timer (net/ipv4/tcp_timer.c:542 (discriminator 7)) Code: 41 55 41 54 55 53 48 8b af b8 08 00 00 48 89 fb 48 85 ed 0f 84 55 01 00 00 0f b6 47 12 3c 03 74 0c 0f b6 47 12 3c 04 74 04 90 <0f> 0b 90 48 8b 85 c0 00 00 00 48 89 ef 48 8b 40 30 e8 6a 4f 06 3e RSP: 0018:ffffc900002f8d40 EFLAGS: 00010293 RAX: 0000000000000002 RBX: ffff888106911400 RCX: 0000000000000017 RD…

 https://cve.radiocsirt.org/vuln/rhsa-2025:21931 RHSA-2025:21931 — Red Hat Security Advisory: kernel security update 2026-10-05T09:33:36.981519+00:00

kernel: NFS: Fix filehandle bounds checking in nfs_fh_to_dentry() kernel: tcp: Clear tcp_sk(sk)->fastopen_rsk in tcp_disconnect()

 https://cve.radiocsirt.org/vuln/rhsa-2025:22388 RHSA-2025:22388 — Red Hat Security Advisory: kernel security update 2026-10-05T09:33:36.981546+00:00

kernel: nbd: fix incomplete validation of ioctl arg kernel: nfsd: handle get_client_locked() failure in nfsd4_setclientid_confirm() kernel: smb: client: fix race with concurrent opens in rename(2) kernel: mm/memory-failure: fix VM_BUG_ON_PAGE(PagePoisoned(page)) when unpoison memory kernel: e1000e: fix heap overflow in e1000_set_eeprom kernel: tcp: Clear tcp_sk(sk)->fastopen_rsk in tcp_disconnect() kernel: Linux kernel: Privilege escalation or Denial of Service via TCP Fast Open vulnerability