Cloudanix VulnDB

CVE-2025-38718

High · 7.8

CVSS

7.8

EPSS

0.2%

Published

Sep 4, 2025

CISA due date

—

Cloudanix analysis

Schedule a fix SSVC: Track

A flaw in how the Linux kernel handles certain network packets could let a local user read private memory or crash the machine.

Exploitation
Local Privilege
Attacker needs
Low Privilege
Complexity
Low
Impact
Full Compromise
Component
OS kernel
Class
Memory Corruption
Remediation
Patch
Effort
Medium
Patch risk
Low

What it actually does

Failure to linearize cloned GSO packets in sctp_rcv allows the receive path to access frag skbs still shared with the original skb, resulting in use-of-uninitialized-memory reads inside sctp_inq_pop and sctp_assoc_bh_rcv.

Why it matters to the business

Local attackers on Linux systems using SCTP may read kernel memory contents or trigger crashes; the issue affects widely deployed kernels but carries low immediate exploitation risk given current threat intelligence.

How an attack unfolds

An attacker with local access creates an SCTP association and sends messages that produce cloned GSO packets; when the kernel processes these packets in sctp_rcv without linearization, subsequent receive-queue handling dereferences uninitialized memory.

How to fix it

Apply the upstream fix (commit d0194e391bb493aa6cec56d177b14df6b29188d5) or upgrade to a kernel that includes the linearization of cloned GSO packets inside sctp_rcv; rebuild and reboot affected systems.

How to confirm the fix worked

Confirm the patch is present by inspecting net/sctp/input.c for the linearization call in sctp_rcv; re-run KMSAN or syzkaller workloads that previously triggered the uninit-value reports.

Typical attack path

  1. Obtain local shell on a Linux host with SCTP enabled
  2. Create SCTP socket and establish association
  3. Transmit messages that trigger GSO cloning in the receive path
  4. Kernel executes sctp_rcv on the cloned skb without linearization
  5. sctp_inq_pop or sctp_assoc_bh_rcv reads uninitialized memory

How to detect it

Search kernel logs and crash reports for KMSAN uninit-value traces referencing sctp_inq_pop or sctp_assoc_bh_rcv; correlate with SCTP socket activity preceding the crash.

  • BUG: KMSAN: uninit-value in sctp_inq_pop
  • sctp_inq_pop+0x15b7/0x1920
  • sctp_assoc_bh_rcv+0x34e/0xbc0
  • sctp_assoc_bh_rcv+0x1a7/0xc50

What your security team should do

  • Patch Linux kernels to the fixed commit on all systems that enable SCTP
  • Disable SCTP module loading via blacklist if the protocol is unused
  • Monitor stable kernel update channels for backports of the fix
  • Include SCTP-related KMSAN signatures in kernel crash monitoring

The record

In the Linux kernel, the following vulnerability has been resolved: sctp: linearize cloned gso packets in sctp_rcv A cloned head skb still shares these frag skbs in fraglist with the original head skb. It's not safe to access these frag skbs. syzbot reported two use-of-uninitialized-memory bugs caused by this: BUG: KMSAN: uninit-value in sctp_inq_pop+0x15b7/0x1920 net/sctp/inqueue.c:211 sctp_inq_pop+0x15b7/0x1920 net/sctp/inqueue.c:211 sctp_assoc_bh_rcv+0x1a7/0xc50 net/sctp/associola.c:998 sctp_inq_push+0x2ef/0x380 net/sctp/inqueue.c:88 sctp_backlog_rcv+0x397/0xdb0 net/sctp/input.c:331 sk_backlog_rcv+0x13b/0x420 include/net/sock.h:1122 __release_sock+0x1da/0x330 net/core/sock.c:3106 release_sock+0x6b/0x250 net/core/sock.c:3660 sctp_wait_for_connect+0x487/0x820 net/sctp/socket.c:9360 sctp_sendmsg_to_asoc+0x1ec1/0x1f00 net/sctp/socket.c:1885 sctp_sendmsg+0x32b9/0x4a80 net/sctp/socket.c:2031 inet_sendmsg+0x25a/0x280 net/ipv4/af_inet.c:851 sock_sendmsg_nosec net/socket.c:718 [inline] and BUG: KMSAN: uninit-value in sctp_assoc_bh_rcv+0x34e/0xbc0 net/sctp/associola.c:987 sctp_assoc_bh_rcv+0x34e/0xbc0 net/sctp/associola.c:987 sctp_inq_push+0x2a3/0x350 net/sctp/inqueue.c:88 sctp_backlog_rcv+0x3c7/0xda0 net/sctp/input.c:331 sk_backlog_rcv+0x142/0x420 include/net/sock.h:1148 __release_sock+0x1d3/0x330 net/core/sock.c:3213 release_sock+0x6b/0x270 net/core/sock.c:3767 sctp_wait_for_connect+0x458/0x820 net/sctp/socket.c:9367 sctp_sendmsg_to_asoc+0x223a/0x2260 net/sctp/socket.c:1886 sctp_sendmsg+0x3910/0x49f0 net/sctp/socket.c:2032 inet_sendmsg+0x269/0x2a0 net/ipv4/af_inet.c:851 sock_sendmsg_nosec net/socket.c:712 [inline] This patch fixes it by linearizing cloned gso packets in sctp_rcv().

Affected packages

Ecosystem Package Introduced Fixed
AlmaLinux:10 kernel 0 6.12.0-55.38.1.el10_0
AlmaLinux:10 kernel-64k 0 6.12.0-55.38.1.el10_0
AlmaLinux:10 kernel-64k-core 0 6.12.0-55.38.1.el10_0
AlmaLinux:10 kernel-64k-debug 0 6.12.0-55.38.1.el10_0
AlmaLinux:10 kernel-64k-debug-core 0 6.12.0-55.38.1.el10_0
AlmaLinux:10 kernel-64k-debug-devel 0 6.12.0-55.38.1.el10_0
AlmaLinux:10 kernel-64k-debug-devel-matched 0 6.12.0-55.38.1.el10_0
AlmaLinux:10 kernel-64k-debug-modules 0 6.12.0-55.38.1.el10_0
AlmaLinux:10 kernel-64k-debug-modules-core 0 6.12.0-55.38.1.el10_0
AlmaLinux:10 kernel-64k-debug-modules-extra 0 6.12.0-55.38.1.el10_0
AlmaLinux:10 kernel-64k-devel 0 6.12.0-55.38.1.el10_0
AlmaLinux:10 kernel-64k-devel-matched 0 6.12.0-55.38.1.el10_0
AlmaLinux:10 kernel-64k-modules 0 6.12.0-55.38.1.el10_0
AlmaLinux:10 kernel-64k-modules-core 0 6.12.0-55.38.1.el10_0
AlmaLinux:10 kernel-64k-modules-extra 0 6.12.0-55.38.1.el10_0
AlmaLinux:10 kernel-abi-stablelists 0 6.12.0-55.38.1.el10_0
AlmaLinux:10 kernel-core 0 6.12.0-55.38.1.el10_0
AlmaLinux:10 kernel-cross-headers 0 6.12.0-55.38.1.el10_0
AlmaLinux:10 kernel-debug 0 6.12.0-55.38.1.el10_0
AlmaLinux:10 kernel-debug-core 0 6.12.0-55.38.1.el10_0
AlmaLinux:10 kernel-debug-devel 0 6.12.0-55.38.1.el10_0
AlmaLinux:10 kernel-debug-devel-matched 0 6.12.0-55.38.1.el10_0
AlmaLinux:10 kernel-debug-modules 0 6.12.0-55.38.1.el10_0
AlmaLinux:10 kernel-debug-modules-core 0 6.12.0-55.38.1.el10_0
AlmaLinux:10 kernel-debug-modules-extra 0 6.12.0-55.38.1.el10_0
AlmaLinux:10 kernel-debug-uki-virt 0 6.12.0-55.38.1.el10_0
AlmaLinux:10 kernel-devel 0 6.12.0-55.38.1.el10_0
AlmaLinux:10 kernel-devel-matched 0 6.12.0-55.38.1.el10_0
AlmaLinux:10 kernel-doc 0 6.12.0-55.38.1.el10_0
AlmaLinux:10 kernel-headers 0 6.12.0-55.38.1.el10_0
AlmaLinux:10 kernel-modules 0 6.12.0-55.38.1.el10_0
AlmaLinux:10 kernel-modules-core 0 6.12.0-55.38.1.el10_0
AlmaLinux:10 kernel-modules-extra 0 6.12.0-55.38.1.el10_0
AlmaLinux:10 kernel-rt 0 6.12.0-55.38.1.el10_0
AlmaLinux:10 kernel-rt-64k 0 6.12.0-55.38.1.el10_0
AlmaLinux:10 kernel-rt-64k-core 0 6.12.0-55.38.1.el10_0
AlmaLinux:10 kernel-rt-64k-debug 0 6.12.0-55.38.1.el10_0
AlmaLinux:10 kernel-rt-64k-debug-core 0 6.12.0-55.38.1.el10_0
AlmaLinux:10 kernel-rt-64k-debug-devel 0 6.12.0-55.38.1.el10_0
AlmaLinux:10 kernel-rt-64k-debug-modules 0 6.12.0-55.38.1.el10_0
AlmaLinux:10 kernel-rt-64k-debug-modules-core 0 6.12.0-55.38.1.el10_0
AlmaLinux:10 kernel-rt-64k-debug-modules-extra 0 6.12.0-55.38.1.el10_0
AlmaLinux:10 kernel-rt-64k-devel 0 6.12.0-55.38.1.el10_0
AlmaLinux:10 kernel-rt-64k-modules 0 6.12.0-55.38.1.el10_0
AlmaLinux:10 kernel-rt-64k-modules-core 0 6.12.0-55.38.1.el10_0
AlmaLinux:10 kernel-rt-64k-modules-extra 0 6.12.0-55.38.1.el10_0
AlmaLinux:10 kernel-rt-core 0 6.12.0-55.38.1.el10_0
AlmaLinux:10 kernel-rt-debug 0 6.12.0-55.38.1.el10_0
AlmaLinux:10 kernel-rt-debug-core 0 6.12.0-55.38.1.el10_0
AlmaLinux:10 kernel-rt-debug-devel 0 6.12.0-55.38.1.el10_0
AlmaLinux:10 kernel-rt-debug-kvm 0 6.12.0-55.38.1.el10_0
AlmaLinux:10 kernel-rt-debug-modules 0 6.12.0-55.38.1.el10_0
AlmaLinux:10 kernel-rt-debug-modules-core 0 6.12.0-55.38.1.el10_0
AlmaLinux:10 kernel-rt-debug-modules-extra 0 6.12.0-55.38.1.el10_0
AlmaLinux:10 kernel-rt-devel 0 6.12.0-55.38.1.el10_0
AlmaLinux:10 kernel-rt-kvm 0 6.12.0-55.38.1.el10_0
AlmaLinux:10 kernel-rt-modules 0 6.12.0-55.38.1.el10_0
AlmaLinux:10 kernel-rt-modules-core 0 6.12.0-55.38.1.el10_0
AlmaLinux:10 kernel-rt-modules-extra 0 6.12.0-55.38.1.el10_0
AlmaLinux:10 kernel-tools 0 6.12.0-55.38.1.el10_0
AlmaLinux:10 kernel-tools-libs 0 6.12.0-55.38.1.el10_0
AlmaLinux:10 kernel-tools-libs-devel 0 6.12.0-55.38.1.el10_0
AlmaLinux:10 kernel-uki-virt 0 6.12.0-55.38.1.el10_0
AlmaLinux:10 kernel-uki-virt-addons 0 6.12.0-55.38.1.el10_0
AlmaLinux:10 kernel-zfcpdump 0 6.12.0-55.38.1.el10_0
AlmaLinux:10 kernel-zfcpdump-core 0 6.12.0-55.38.1.el10_0
AlmaLinux:10 kernel-zfcpdump-devel 0 6.12.0-55.38.1.el10_0
AlmaLinux:10 kernel-zfcpdump-devel-matched 0 6.12.0-55.38.1.el10_0
AlmaLinux:10 kernel-zfcpdump-modules 0 6.12.0-55.38.1.el10_0
AlmaLinux:10 kernel-zfcpdump-modules-core 0 6.12.0-55.38.1.el10_0
AlmaLinux:10 kernel-zfcpdump-modules-extra 0 6.12.0-55.38.1.el10_0
AlmaLinux:10 libperf 0 6.12.0-55.38.1.el10_0
AlmaLinux:10 perf 0 6.12.0-55.38.1.el10_0
AlmaLinux:10 python3-perf 0 6.12.0-55.38.1.el10_0
AlmaLinux:10 rtla 0 6.12.0-55.38.1.el10_0
AlmaLinux:10 rv 0 6.12.0-55.38.1.el10_0
AlmaLinux:8 bpftool 0 4.18.0-553.77.1.el8_10
AlmaLinux:8 kernel 0 4.18.0-553.77.1.el8_10
AlmaLinux:8 kernel-abi-stablelists 0 4.18.0-553.77.1.el8_10
AlmaLinux:8 kernel-core 0 4.18.0-553.77.1.el8_10
AlmaLinux:8 kernel-cross-headers 0 4.18.0-553.77.1.el8_10
AlmaLinux:8 kernel-debug 0 4.18.0-553.77.1.el8_10
AlmaLinux:8 kernel-debug-core 0 4.18.0-553.77.1.el8_10
AlmaLinux:8 kernel-debug-devel 0 4.18.0-553.77.1.el8_10
AlmaLinux:8 kernel-debug-modules 0 4.18.0-553.77.1.el8_10
AlmaLinux:8 kernel-debug-modules-extra 0 4.18.0-553.77.1.el8_10
AlmaLinux:8 kernel-devel 0 4.18.0-553.77.1.el8_10
AlmaLinux:8 kernel-doc 0 4.18.0-553.77.1.el8_10
AlmaLinux:8 kernel-headers 0 4.18.0-553.77.1.el8_10
AlmaLinux:8 kernel-modules 0 4.18.0-553.77.1.el8_10
AlmaLinux:8 kernel-modules-extra 0 4.18.0-553.77.1.el8_10
AlmaLinux:8 kernel-rt 0 4.18.0-553.77.1.rt7.418.el8_10
AlmaLinux:8 kernel-rt-core 0 4.18.0-553.77.1.rt7.418.el8_10
AlmaLinux:8 kernel-rt-debug 0 4.18.0-553.77.1.rt7.418.el8_10
AlmaLinux:8 kernel-rt-debug-core 0 4.18.0-553.77.1.rt7.418.el8_10
AlmaLinux:8 kernel-rt-debug-devel 0 4.18.0-553.77.1.rt7.418.el8_10
AlmaLinux:8 kernel-rt-debug-modules 0 4.18.0-553.77.1.rt7.418.el8_10
AlmaLinux:8 kernel-rt-debug-modules-extra 0 4.18.0-553.77.1.rt7.418.el8_10
AlmaLinux:8 kernel-rt-devel 0 4.18.0-553.77.1.rt7.418.el8_10
AlmaLinux:8 kernel-rt-modules 0 4.18.0-553.77.1.rt7.418.el8_10
AlmaLinux:8 kernel-rt-modules-extra 0 4.18.0-553.77.1.rt7.418.el8_10
AlmaLinux:8 kernel-tools 0 4.18.0-553.77.1.el8_10
AlmaLinux:8 kernel-tools-libs 0 4.18.0-553.77.1.el8_10
AlmaLinux:8 kernel-tools-libs-devel 0 4.18.0-553.77.1.el8_10
AlmaLinux:8 kernel-zfcpdump 0 4.18.0-553.77.1.el8_10
AlmaLinux:8 kernel-zfcpdump-core 0 4.18.0-553.77.1.el8_10
AlmaLinux:8 kernel-zfcpdump-devel 0 4.18.0-553.77.1.el8_10
AlmaLinux:8 kernel-zfcpdump-modules 0 4.18.0-553.77.1.el8_10
AlmaLinux:8 kernel-zfcpdump-modules-extra 0 4.18.0-553.77.1.el8_10
AlmaLinux:8 perf 0 4.18.0-553.77.1.el8_10
AlmaLinux:8 python3-perf 0 4.18.0-553.77.1.el8_10
AlmaLinux:9 kernel 0 5.14.0-570.49.1.el9_6
AlmaLinux:9 kernel-64k 0 5.14.0-570.49.1.el9_6
AlmaLinux:9 kernel-64k-core 0 5.14.0-570.49.1.el9_6
AlmaLinux:9 kernel-64k-debug 0 5.14.0-570.49.1.el9_6
AlmaLinux:9 kernel-64k-debug-core 0 5.14.0-570.49.1.el9_6
AlmaLinux:9 kernel-64k-debug-devel 0 5.14.0-570.49.1.el9_6
AlmaLinux:9 kernel-64k-debug-devel-matched 0 5.14.0-570.49.1.el9_6
AlmaLinux:9 kernel-64k-debug-modules 0 5.14.0-570.49.1.el9_6
AlmaLinux:9 kernel-64k-debug-modules-core 0 5.14.0-570.49.1.el9_6
AlmaLinux:9 kernel-64k-debug-modules-extra 0 5.14.0-570.49.1.el9_6
AlmaLinux:9 kernel-64k-devel 0 5.14.0-570.49.1.el9_6
AlmaLinux:9 kernel-64k-devel-matched 0 5.14.0-570.49.1.el9_6
AlmaLinux:9 kernel-64k-modules 0 5.14.0-570.49.1.el9_6
AlmaLinux:9 kernel-64k-modules-core 0 5.14.0-570.49.1.el9_6
AlmaLinux:9 kernel-64k-modules-extra 0 5.14.0-570.49.1.el9_6
AlmaLinux:9 kernel-abi-stablelists 0 5.14.0-570.49.1.el9_6
AlmaLinux:9 kernel-core 0 5.14.0-570.49.1.el9_6
AlmaLinux:9 kernel-cross-headers 0 5.14.0-570.49.1.el9_6
AlmaLinux:9 kernel-debug 0 5.14.0-570.49.1.el9_6
AlmaLinux:9 kernel-debug-core 0 5.14.0-570.49.1.el9_6
AlmaLinux:9 kernel-debug-devel 0 5.14.0-570.49.1.el9_6
AlmaLinux:9 kernel-debug-devel-matched 0 5.14.0-570.49.1.el9_6
AlmaLinux:9 kernel-debug-modules 0 5.14.0-570.49.1.el9_6
AlmaLinux:9 kernel-debug-modules-core 0 5.14.0-570.49.1.el9_6
AlmaLinux:9 kernel-debug-modules-extra 0 5.14.0-570.49.1.el9_6
AlmaLinux:9 kernel-debug-uki-virt 0 5.14.0-570.49.1.el9_6
AlmaLinux:9 kernel-devel 0 5.14.0-570.49.1.el9_6
AlmaLinux:9 kernel-devel-matched 0 5.14.0-570.49.1.el9_6
AlmaLinux:9 kernel-doc 0 5.14.0-570.49.1.el9_6
AlmaLinux:9 kernel-headers 0 5.14.0-570.49.1.el9_6
AlmaLinux:9 kernel-modules 0 5.14.0-570.49.1.el9_6
AlmaLinux:9 kernel-modules-core 0 5.14.0-570.49.1.el9_6
AlmaLinux:9 kernel-modules-extra 0 5.14.0-570.49.1.el9_6
AlmaLinux:9 kernel-rt 0 5.14.0-570.49.1.el9_6
AlmaLinux:9 kernel-rt-64k 0 5.14.0-570.49.1.el9_6
AlmaLinux:9 kernel-rt-64k-core 0 5.14.0-570.49.1.el9_6
AlmaLinux:9 kernel-rt-64k-debug 0 5.14.0-570.49.1.el9_6
AlmaLinux:9 kernel-rt-64k-debug-core 0 5.14.0-570.49.1.el9_6
AlmaLinux:9 kernel-rt-64k-debug-devel 0 5.14.0-570.49.1.el9_6
AlmaLinux:9 kernel-rt-64k-debug-modules 0 5.14.0-570.49.1.el9_6
AlmaLinux:9 kernel-rt-64k-debug-modules-core 0 5.14.0-570.49.1.el9_6
AlmaLinux:9 kernel-rt-64k-debug-modules-extra 0 5.14.0-570.49.1.el9_6
AlmaLinux:9 kernel-rt-64k-devel 0 5.14.0-570.49.1.el9_6
AlmaLinux:9 kernel-rt-64k-modules 0 5.14.0-570.49.1.el9_6
AlmaLinux:9 kernel-rt-64k-modules-core 0 5.14.0-570.49.1.el9_6
AlmaLinux:9 kernel-rt-64k-modules-extra 0 5.14.0-570.49.1.el9_6
AlmaLinux:9 kernel-rt-core 0 5.14.0-570.49.1.el9_6
AlmaLinux:9 kernel-rt-debug 0 5.14.0-570.49.1.el9_6
AlmaLinux:9 kernel-rt-debug-core 0 5.14.0-570.49.1.el9_6
AlmaLinux:9 kernel-rt-debug-devel 0 5.14.0-570.49.1.el9_6
AlmaLinux:9 kernel-rt-debug-kvm 0 5.14.0-570.49.1.el9_6
AlmaLinux:9 kernel-rt-debug-modules 0 5.14.0-570.49.1.el9_6
AlmaLinux:9 kernel-rt-debug-modules-core 0 5.14.0-570.49.1.el9_6
AlmaLinux:9 kernel-rt-debug-modules-extra 0 5.14.0-570.49.1.el9_6
AlmaLinux:9 kernel-rt-devel 0 5.14.0-570.49.1.el9_6
AlmaLinux:9 kernel-rt-kvm 0 5.14.0-570.49.1.el9_6
AlmaLinux:9 kernel-rt-modules 0 5.14.0-570.49.1.el9_6
AlmaLinux:9 kernel-rt-modules-core 0 5.14.0-570.49.1.el9_6
AlmaLinux:9 kernel-rt-modules-extra 0 5.14.0-570.49.1.el9_6
AlmaLinux:9 kernel-tools 0 5.14.0-570.49.1.el9_6
AlmaLinux:9 kernel-tools-libs 0 5.14.0-570.49.1.el9_6
AlmaLinux:9 kernel-tools-libs-devel 0 5.14.0-570.49.1.el9_6
AlmaLinux:9 kernel-uki-virt 0 5.14.0-570.49.1.el9_6
AlmaLinux:9 kernel-uki-virt-addons 0 5.14.0-570.49.1.el9_6
AlmaLinux:9 kernel-zfcpdump 0 5.14.0-570.49.1.el9_6
AlmaLinux:9 kernel-zfcpdump-core 0 5.14.0-570.49.1.el9_6
AlmaLinux:9 kernel-zfcpdump-devel 0 5.14.0-570.49.1.el9_6
AlmaLinux:9 kernel-zfcpdump-devel-matched 0 5.14.0-570.49.1.el9_6
AlmaLinux:9 kernel-zfcpdump-modules 0 5.14.0-570.49.1.el9_6
AlmaLinux:9 kernel-zfcpdump-modules-core 0 5.14.0-570.49.1.el9_6
AlmaLinux:9 kernel-zfcpdump-modules-extra 0 5.14.0-570.49.1.el9_6
AlmaLinux:9 libperf 0 5.14.0-570.49.1.el9_6
AlmaLinux:9 perf 0 5.14.0-570.49.1.el9_6
AlmaLinux:9 python3-perf 0 5.14.0-570.49.1.el9_6
AlmaLinux:9 rtla 0 5.14.0-570.49.1.el9_6
AlmaLinux:9 rv 0 5.14.0-570.49.1.el9_6
Debian:11 linux 0 No fix
Debian:12 linux 0 No fix
Debian:13 linux 0 6.12.43-1
Debian:14 linux 0 6.16.3-1
Linux Kernel 4.8.0 5.4.297
Mageia:9 kernel 0 6.6.105-1.mga9
Mageia:9 kernel-linus 0 6.6.105-1.mga9
Mageia:9 kmod-virtualbox 0 7.1.10-10.mga9
Mageia:9 kmod-xtables-addons 0 3.24-86.mga9
Mageia:9 mageia-repos 0 9-4.mga9
Mageia:9 meta-task 0 9-4.mga9
SUSE:Linux Enterprise High Availability Extension 15 SP6 kernel-default 0 6.4.0-150600.23.78.1
SUSE:Linux Enterprise High Availability Extension 15 SP7 kernel-default 0 6.4.0-150700.53.22.1

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