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Google: sys-kernel/csql-kernel-6_6: security update to 19165.0.0

medium Tenable Cloud Security Plugin ID 454267

Description

There are packages installed that are affected by a vulnerability referenced in the following CVE:

 - In the Linux kernel, the following vulnerability has been resolved: tcp: correct handling of extreme
 memory squeeze Testing with iperf3 using the "pasta" protocol splicer has revealed a problem in the way
 tcp handles window advertising in extreme memory squeeze situations. Under memory pressure, a socket
 endpoint may temporarily advertise a zero-sized window, but this is not stored as part of the socket data.
 The reasoning behind this is that it is considered a temporary setting which shouldn't influence any
 further calculations. However, if we happen to stall at an unfortunate value of the current window size,
 the algorithm selecting a new value will consistently fail to advertise a non-zero window once we have
 freed up enough memory. This means that this side's notion of the current window size is different from
 the one last advertised to the peer, causing the latter to not send any data to resolve the sitution. The
 problem occurs on the iperf3 server side, and the socket in question is a completely regular socket with
 the default settings for the fedora40 kernel. We do not use SO_PEEK or SO_RCVBUF on the socket. The
 following excerpt of a logging session, with own comments added, shows more in detail what is happening:
 // tcp_v4_rcv(->) // tcp_rcv_established(->) [5201<->39222]: ==== Activating log @
 net/ipv4/tcp_input.c/tcp_data_queue()/5257 ==== [5201<->39222]: tcp_data_queue(->) [5201<->39222]:
 DROPPING skb [265600160..265665640], reason: SKB_DROP_REASON_PROTO_MEM [rcv_nxt 265600160, rcv_wnd 262144,
 snt_ack 265469200, win_now 131184] [copied_seq 259909392->260034360 (124968), unread 5565800, qlen 85,
 ofoq 0] [OFO queue: gap: 65480, len: 0] [5201<->39222]: tcp_data_queue(<-) [5201<->39222]:
 __tcp_transmit_skb(->) [tp->rcv_wup: 265469200, tp->rcv_wnd: 262144, tp->rcv_nxt 265600160]
 [5201<->39222]: tcp_select_window(->) [5201<->39222]: (inet_csk(sk)->icsk_ack.pending & ICSK_ACK_NOMEM) ?
 --> TRUE [tp->rcv_wup: 265469200, tp->rcv_wnd: 262144, tp->rcv_nxt 265600160] returning 0 [5201<->39222]:
 tcp_select_window(<-) [5201<->39222]: ADVERTISING WIN 0, ACK_SEQ: 265600160 [5201<->39222]:
 [__tcp_transmit_skb(<-) [5201<->39222]: tcp_rcv_established(<-) [5201<->39222]: tcp_v4_rcv(<-) // Receive
 queue is at 85 buffers and we are out of memory. // We drop the incoming buffer, although it is in
 sequence, and decide // to send an advertisement with a window of zero. // We don't update tp->rcv_wnd and
 tp->rcv_wup accordingly, which means // we unconditionally shrink the window. [5201<->39222]:
 tcp_recvmsg_locked(->) [5201<->39222]: __tcp_cleanup_rbuf(->) tp->rcv_wup: 265469200, tp->rcv_wnd: 262144,
 tp->rcv_nxt 265600160 [5201<->39222]: [new_win = 0, win_now = 131184, 2 * win_now = 262368]
 [5201<->39222]: [new_win >= (2 * win_now) ? --> time_to_ack = 0] [5201<->39222]: NOT calling
 tcp_send_ack() [tp->rcv_wup: 265469200, tp->rcv_wnd: 262144, tp->rcv_nxt 265600160] [5201<->39222]:
 __tcp_cleanup_rbuf(<-) [rcv_nxt 265600160, rcv_wnd 262144, snt_ack 265469200, win_now 131184] [copied_seq
 260040464->260040464 (0), unread 5559696, qlen 85, ofoq 0] returning 6104 bytes [5201<->39222]:
 tcp_recvmsg_locked(<-) // After each read, the algorithm for calculating the new receive // window in
 __tcp_cleanup_rbuf() finds it is too small to advertise // or to update tp->rcv_wnd. // Meanwhile, the
 peer thinks the window is zero, and will not send // any more data to trigger an update from the interrupt
 mode side. [5201<->39222]: tcp_recvmsg_locked(->) [5201<->39222]: __tcp_cleanup_rbuf(->) tp->rcv_wup:
 265469200, tp->rcv_wnd: 262144, tp->rcv_nxt 265600160 [5201<->39222]: [new_win = 262144, win_now = 131184,
 2 * win_n ---truncated--- (CVE-2025-21710)

Solution

Update the sys-kernel/csql-kernel-6_6 library and its related packages to version 19165.0.0 or later.

See Also

https://storage.googleapis.com/cos-oval-vulnerability-feed/cos-125.oval.xml.tar.gz

Plugin Details

Severity: Medium

ID: 454267

Version: Revision 1.1

Type: Local

Published: 10/1/2026

Updated: 10/1/2026

Risk Information

VPR

Risk Factor: Low

Score: 3

Percentile: 23.37

Vendor

Vendor Severity: MEDIUM

CVSS v2

Risk Factor: Medium

Base Score: 4.6

Temporal Score: 3.4

Vector: CVSS2#AV:L/AC:L/Au:S/C:N/I:N/A:C

CVSS Score Source: CVE-2025-21710

CVSS v3

Risk Factor: Medium

Base Score: 5.5

Temporal Score: 4.8

Vector: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C

Vulnerability Information

Exploit Ease: No known exploits are available

Vulnerability Publication Date: 2/27/2025

Reference Information

CVE: CVE-2025-21710