Unrated severityNVD Advisory· Published Jun 19, 2024· Updated May 4, 2025

mptcp: clear 'kern' flag from fallback sockets

CVE-2021-47593

Description

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

The mptcp ULP extension relies on sk->sk_sock_kern being set correctly: It prevents setsockopt(fd, IPPROTO_TCP, TCP_ULP, "mptcp", 6); from working for plain tcp sockets (any userspace-exposed socket).

But in case of fallback, accept() can return a plain tcp sk. In such case, sk is still tagged as 'kernel' and setsockopt will work.

This will crash the kernel, The subflow extension has a NULL ctx->conn mptcp socket:

BUG: KASAN: null-ptr-deref in subflow_data_ready+0x181/0x2b0 Call Trace: tcp_data_ready+0xf8/0x370 [..]

Affected products

osv-coords48 versions
pkg:rpm/opensuse/dtb-aarch64&distro=openSUSE%20Leap%2015.5 pkg:rpm/opensuse/kernel-64kb&distro=openSUSE%20Leap%2015.5 pkg:rpm/opensuse/kernel-azure&distro=openSUSE%20Leap%2015.5 pkg:rpm/opensuse/kernel-debug&distro=openSUSE%20Leap%2015.5 pkg:rpm/opensuse/kernel-default-base&distro=openSUSE%20Leap%2015.5 pkg:rpm/opensuse/kernel-default-base&distro=openSUSE%20Leap%20Micro%205.5 pkg:rpm/opensuse/kernel-default&distro=openSUSE%20Leap%2015.5 pkg:rpm/opensuse/kernel-default&distro=openSUSE%20Leap%20Micro%205.5 pkg:rpm/opensuse/kernel-docs&distro=openSUSE%20Leap%2015.5 pkg:rpm/opensuse/kernel-kvmsmall&distro=openSUSE%20Leap%2015.5 pkg:rpm/opensuse/kernel-obs-build&distro=openSUSE%20Leap%2015.5 pkg:rpm/opensuse/kernel-obs-qa&distro=openSUSE%20Leap%2015.5 pkg:rpm/opensuse/kernel-rt_debug&distro=openSUSE%20Leap%2015.5 pkg:rpm/opensuse/kernel-rt&distro=openSUSE%20Leap%2015.5 pkg:rpm/opensuse/kernel-rt&distro=openSUSE%20Leap%20Micro%205.5 pkg:rpm/opensuse/kernel-source-azure&distro=openSUSE%20Leap%2015.5 pkg:rpm/opensuse/kernel-source&distro=openSUSE%20Leap%2015.5 pkg:rpm/opensuse/kernel-source-rt&distro=openSUSE%20Leap%2015.5 pkg:rpm/opensuse/kernel-syms-azure&distro=openSUSE%20Leap%2015.5 pkg:rpm/opensuse/kernel-syms&distro=openSUSE%20Leap%2015.5 pkg:rpm/opensuse/kernel-syms-rt&distro=openSUSE%20Leap%2015.5 pkg:rpm/opensuse/kernel-zfcpdump&distro=openSUSE%20Leap%2015.5 pkg:rpm/suse/kernel-64kb&distro=SUSE%20Linux%20Enterprise%20Module%20for%20Basesystem%2015%20SP5 pkg:rpm/suse/kernel-azure&distro=SUSE%20Linux%20Enterprise%20Module%20for%20Public%20Cloud%2015%20SP5 pkg:rpm/suse/kernel-default-base&distro=SUSE%20Linux%20Enterprise%20Micro%205.5 pkg:rpm/suse/kernel-default-base&distro=SUSE%20Linux%20Enterprise%20Module%20for%20Basesystem%2015%20SP5 pkg:rpm/suse/kernel-default&distro=SUSE%20Linux%20Enterprise%20High%20Availability%20Extension%2015%20SP5 pkg:rpm/suse/kernel-default&distro=SUSE%20Linux%20Enterprise%20Live%20Patching%2015%20SP5 pkg:rpm/suse/kernel-default&distro=SUSE%20Linux%20Enterprise%20Micro%205.5 pkg:rpm/suse/kernel-default&distro=SUSE%20Linux%20Enterprise%20Module%20for%20Basesystem%2015%20SP5 pkg:rpm/suse/kernel-default&distro=SUSE%20Linux%20Enterprise%20Module%20for%20Legacy%2015%20SP5 pkg:rpm/suse/kernel-default&distro=SUSE%20Linux%20Enterprise%20Workstation%20Extension%2015%20SP5 pkg:rpm/suse/kernel-docs&distro=SUSE%20Linux%20Enterprise%20Module%20for%20Development%20Tools%2015%20SP5 pkg:rpm/suse/kernel-livepatch-SLE15-SP5-RT_Update_18&distro=SUSE%20Linux%20Enterprise%20Live%20Patching%2015%20SP5 pkg:rpm/suse/kernel-livepatch-SLE15-SP5_Update_17&distro=SUSE%20Linux%20Enterprise%20Live%20Patching%2015%20SP5 pkg:rpm/suse/kernel-obs-build&distro=SUSE%20Linux%20Enterprise%20Module%20for%20Development%20Tools%2015%20SP5 pkg:rpm/suse/kernel-rt_debug&distro=SUSE%20Real%20Time%20Module%2015%20SP5 pkg:rpm/suse/kernel-rt&distro=SUSE%20Linux%20Enterprise%20Micro%205.5 pkg:rpm/suse/kernel-rt&distro=SUSE%20Real%20Time%20Module%2015%20SP5 pkg:rpm/suse/kernel-source-azure&distro=SUSE%20Linux%20Enterprise%20Module%20for%20Public%20Cloud%2015%20SP5 pkg:rpm/suse/kernel-source&distro=SUSE%20Linux%20Enterprise%20Module%20for%20Basesystem%2015%20SP5 pkg:rpm/suse/kernel-source&distro=SUSE%20Linux%20Enterprise%20Module%20for%20Development%20Tools%2015%20SP5 pkg:rpm/suse/kernel-source-rt&distro=SUSE%20Linux%20Enterprise%20Micro%205.5 pkg:rpm/suse/kernel-source-rt&distro=SUSE%20Real%20Time%20Module%2015%20SP5 pkg:rpm/suse/kernel-syms-azure&distro=SUSE%20Linux%20Enterprise%20Module%20for%20Public%20Cloud%2015%20SP5 pkg:rpm/suse/kernel-syms&distro=SUSE%20Linux%20Enterprise%20Module%20for%20Development%20Tools%2015%20SP5 pkg:rpm/suse/kernel-syms-rt&distro=SUSE%20Real%20Time%20Module%2015%20SP5 pkg:rpm/suse/kernel-zfcpdump&distro=SUSE%20Linux%20Enterprise%20Module%20for%20Basesystem%2015%20SP5
< 5.14.21-150500.55.73.1+ 47 more
- (no CPE)range: < 5.14.21-150500.55.73.1
- (no CPE)range: < 5.14.21-150500.55.73.1
- (no CPE)range: < 5.14.21-150500.33.63.1
- (no CPE)range: < 5.14.21-150500.55.73.1
- (no CPE)range: < 5.14.21-150500.55.73.1.150500.6.33.8
- (no CPE)range: < 5.14.21-150500.55.73.1.150500.6.33.8
- (no CPE)range: < 5.14.21-150500.55.73.1
- (no CPE)range: < 5.14.21-150500.55.73.1
- (no CPE)range: < 5.14.21-150500.55.73.2
- (no CPE)range: < 5.14.21-150500.55.73.1
- (no CPE)range: < 5.14.21-150500.55.73.1
- (no CPE)range: < 5.14.21-150500.55.73.1
- (no CPE)range: < 5.14.21-150500.13.64.1
- (no CPE)range: < 5.14.21-150500.13.64.1
- (no CPE)range: < 5.14.21-150500.13.64.1
- (no CPE)range: < 5.14.21-150500.33.63.1
- (no CPE)range: < 5.14.21-150500.55.73.1
- (no CPE)range: < 5.14.21-150500.13.64.1
- (no CPE)range: < 5.14.21-150500.33.63.1
- (no CPE)range: < 5.14.21-150500.55.73.1
- (no CPE)range: < 5.14.21-150500.13.64.1
- (no CPE)range: < 5.14.21-150500.55.73.1
- (no CPE)range: < 5.14.21-150500.55.73.1
- (no CPE)range: < 5.14.21-150500.33.63.1
- (no CPE)range: < 5.14.21-150500.55.73.1.150500.6.33.8
- (no CPE)range: < 5.14.21-150500.55.73.1.150500.6.33.8
- (no CPE)range: < 5.14.21-150500.55.73.1
- (no CPE)range: < 5.14.21-150500.55.73.1
- (no CPE)range: < 5.14.21-150500.55.73.1
- (no CPE)range: < 5.14.21-150500.55.73.1
- (no CPE)range: < 5.14.21-150500.55.73.1
- (no CPE)range: < 5.14.21-150500.55.73.1
- (no CPE)range: < 5.14.21-150500.55.73.2
- (no CPE)range: < 1-150500.11.3.1
- (no CPE)range: < 1-150500.11.3.1
- (no CPE)range: < 5.14.21-150500.55.73.1
- (no CPE)range: < 5.14.21-150500.13.64.1
- (no CPE)range: < 5.14.21-150500.13.64.1
- (no CPE)range: < 5.14.21-150500.13.64.1
- (no CPE)range: < 5.14.21-150500.33.63.1
- (no CPE)range: < 5.14.21-150500.55.73.1
- (no CPE)range: < 5.14.21-150500.55.73.1
- (no CPE)range: < 5.14.21-150500.13.64.1
- (no CPE)range: < 5.14.21-150500.13.64.1
- (no CPE)range: < 5.14.21-150500.33.63.1
- (no CPE)range: < 5.14.21-150500.55.73.1
- (no CPE)range: < 5.14.21-150500.13.64.1
- (no CPE)range: < 5.14.21-150500.55.73.1
Linux/Linuxcpe-rescue
Range: 5.6

Patches

No patches discovered yet.

Vulnerability mechanics

AI mechanics synthesis has not run for this CVE yet.

References

News mentions

No linked articles in our index yet.

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