high 7.8

CVE-2025-39913 json

tcp_bpf: Call sk_msg_free() when tcp_bpf_send_verdict() fails to allocate psock->cork.

published 2025-10-01 13 mo ago modified 2026-10-19 20 d ago also EUVD-2025-32662

cvss: 7.8; version 3.1, NVD
cisa kev: Not listed; not in CISA's catalog
epss: 0.2%; EPSS 0.2% chance of exploitation in 30 days, percentile 8%
public exploits: 0; none known

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

syzbot reported the splat below. [0]

The repro does the following:

1. Load a sk_msg prog that calls bpf_msg_cork_bytes(msg, cork_bytes) 2. Attach the prog to a SOCKMAP 3. Add a socket to the SOCKMAP 4. Activate fault injection 5. Send data less than cork_bytes

At 5., the data is carried over to the next sendmsg() as it is smaller than the cork_bytes specified by bpf_msg_cork_bytes().

Then, tcp_bpf_send_verdict() tries to allocate psock->cork to hold the data, but this fails silently due to fault injection + __GFP_NOWARN.

If the allocation fails, we need to revert the sk->sk_forward_alloc change done by sk_msg_alloc().

Let's call sk_msg_free() when tcp_bpf_send_verdict fails to allocate psock->cork.

The "*copied" also needs to be updated such that a proper error can be returned to the caller, sendmsg. It fails to allocate psock->cork. Nothing has been corked so far, so this patch simply sets "*copied" to 0.

[0]: WARNING: net/ipv4/af_inet.c:156 at inet_sock_destruct+0x623/0x730 net/ipv4/af_inet.c:156, CPU#1: syz-executor/5983 Modules linked in: CPU: 1 UID: 0 PID: 5983 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 RIP: 0010:inet_sock_destruct+0x623/0x730 net/ipv4/af_inet.c:156 Code: 0f 0b 90 e9 62 fe ff ff e8 7a db b5 f7 90 0f 0b 90 e9 95 fe ff ff e8 6c db b5 f7 90 0f 0b 90 e9 bb fe ff ff e8 5e db b5 f7 90 <0f> 0b 90 e9 e1 fe ff ff 89 f9 80 e1 07 80 c1 03 38 c1 0f 8c 9f fc RSP: 0018:ffffc90000a08b48 EFLAGS: 00010246 RAX: ffffffff8a09d0b2 RBX: dffffc0000000000 RCX: ffff888024a23c80 RDX: 0000000000000100 RSI: 0000000000000fff RDI: 0000000000000000 RBP: 0000000000000fff R08: ffff88807e07c627 R09: 1ffff1100fc0f8c4 R10: dffffc0000000000 R11: ffffed100fc0f8c5 R12: ffff88807e07c380 R13: dffffc0000000000 R14: ffff88807e07c60c R15: 1ffff1100fc0f872 FS: 00005555604c4500(0000) GS:ffff888125af1000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00005555604df5c8 CR3: 0000000032b06000 CR4: 00000000003526f0 Call Trace: <IRQ> __sk_destruct+0x86/0x660 net/core/sock.c:2339 rcu_do_batch kernel/rcu/tree.c:2605 [inline] rcu_core+0xca8/0x1770 kernel/rcu/tree.c:2861 handle_softirqs+0x286/0x870 kernel/softirq.c:579 __do_softirq kernel/softirq.c:613 [inline] invoke_softirq kernel/softirq.c:453 [inline] __irq_exit_rcu+0xca/0x1f0 kernel/softirq.c:680 irq_exit_rcu+0x9/0x30 kernel/softirq.c:696 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1052 [inline] sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1052 </IRQ>

Patch / fix

fixed in 2 distros 5 links 8

Linux Linux 5.4.300, 5.10.245, 5.15.194, 6.1.153, 6.6.107, 6.12.48, 6.16.8, 6.17
Siemens RUGGEDCOM RST2428P V4.0

debian ubuntu suse opensuse azure linux

linux Debian 12 6.1.153-1
linux Debian 13 6.12.48-1
linux Debian 14 6.16.8-1

debian advisories DEBIAN-CVE-2025-39913

linux Ubuntu 22.04 LTS 5.15.0-170.180
linux Ubuntu 24.04 LTS 6.8.0-106.106
linux-aws Ubuntu 22.04 LTS 5.15.0-1100.107
linux-aws Ubuntu 24.04 LTS 6.8.0-1050.53
linux-gcp Ubuntu 22.04 LTS 5.15.0-1100.109
linux-gcp Ubuntu 24.04 LTS 6.8.0-1052.55
linux-gke Ubuntu 22.04 LTS 5.15.0-1096.102
linux-gke Ubuntu 24.04 LTS 6.8.0-1048.53

ubuntu advisories UBUNTU-CVE-2025-39913

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

kernel-rt Linux Micro 6.1, Linux Micro 6.0 6.4.0-40.1
kernel-source-rt Linux Micro 6.1, Linux Micro 6.0 6.4.0-40.1
kernel-rt Linux Micro 6.2 6.12.0-160000.26.1
kernel-64kb SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 6.12.0-160000.26.1
kernel-source SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 6.12.0-160000.26.1
kernel-default SLES 16.0, SLE High Availability Extension 16.0, Linux Micro 6.2 +1 more 6.12.0-160000.26.1
kernel-default-base SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 6.12.0-160000.26.1.160000.2.7
kernel-syms SLES 16.0, Linux Micro Extras 6.2, SLES for SAP applications 16.0 6.12.0-160000.26.1

suse advisories SUSE-SU-2026:20845-1 SUSE-SU-2026:20876-1 SUSE-SU-2026:20555-1 SUSE-SU-2026:20599-1 SUSE-SU-2026:20615-1 SUSE-SU-2026:20570-1

kernel-rt openSUSE Leap 16.0 6.12.0-160000.26.1
dtb-aarch64 openSUSE Leap 16.0 6.12.0-160000.26.1
kernel-64kb openSUSE Leap 16.0 6.12.0-160000.26.1
kernel-syms openSUSE Leap 16.0 6.12.0-160000.26.1
kernel-azure openSUSE Leap 16.0 6.12.0-160000.26.1
kernel-obs-qa openSUSE Leap 16.0 6.12.0-160000.26.1
kernel-source openSUSE Leap 16.0 6.12.0-160000.26.1
kernel-default openSUSE Leap 16.0 6.12.0-160000.26.1

opensuse advisories openSUSE-SU-2026:20287-1

kernel Azure Linux 3.0 6.6.112.1-1
kernel CBL-Mariner 2.0 5.15.200.1-1

azure linux advisories AZL-68049 AZL-74757

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2025-39913 updated 2026-11-07 cvss 4.4

kernel: tcp_bpf: Call sk_msg_free() when tcp_bpf_send_verdict() fails to allocate psock->cork

Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 more Red Hat Enterprise Linux 9 rv, perf, rtla, kernel, bpftool, libperf, +83 more Red Hat Enterprise Linux 10 kernel
affected: no fix available “Fix deferred”
Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more
not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

cisa ICSA-26-188-05 updated 2026-07-07 cvss 5.5

Siemens SINEC OS

Siemens RUGGEDCOM RST2428P (6GK6242-6PA00) < 4.0
affected: fixed in V4.0 support.industry.siemens.com

Facts from CISA's republication of the vendor's own advisory (CSAF); the linked advisory is the authoritative source. CISA notification · csaf

CISA SSVC

Exploitation: none
Automatable: no
Technical impact: total
Assessed: 4 mo ago (2026-06-10)

Exploit prediction

0.19% chance of exploitation in the next 30 days, higher than 8% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
NVD	3.1	7.8	CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected products

Linux Linux
Siemens RUGGEDCOM RST2428P

Classification

Technology feeds

Linux kernel rss critical rss

References

Sources

CVE List CVE-2025-39913
NVD CVE-2025-39913

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary