Upstream information
Description
In the Linux kernel, the following vulnerability has been resolved:mptcp: avoid combining some incoming suboptions
Some MPTCP suboptions are mutually exclusive according to the RFC8684,
but also because in different places, the code doesn't expect some
combinations to be present. That's specially true for suboptions that
would be present twice, but with different attributes.
The new restrictions are the same as the ones applied on the output
side, with mptcp_write_options. The same rules can be reused with a
small fix: an MP_FASTCLOSE can be used with a DSS when the sender picks
this option [1], which is not the case on Linux. Here are the rules:
Which options can be used together?
X: mutually exclusive
O: often used together
C: can be used together in some cases
P: could be used together but we prefer not to (optimisations)
| Opt: | MPC | MPJ | DSS | ADD | RM | PRIO | FAIL | FC |
|------|------|------|------|------|------|------|------|------|
| MPC |------|------|------|------|------|------|------|------|
| MPJ | X |------|------|------|------|------|------|------|
| DSS | X | X |------|------|------|------|------|------|
| ADD | X | X | P |------|------|------|------|------|
| RM | C | C | C | P |------|------|------|------|
| PRIO | X | C | C | C | C |------|------|------|
| FAIL | X | X | C | X | X | X |------|------|
| FC | X | X | P | X | X | X | X |------|
| RST | X | X | X | X | X | X | O | O |
|------|------|------|------|------|------|------|------|------|
The only difference is with the 'P': another stack could send and
ADD_ADDR with other suboptions (DSS, RM_ADDR), and this should be
allowed.
A few points of attention:
- In theory, an MP_CAPABLE could be used with a RM_ADDR, but there is
no reason to add it with a SYN. Note that even with a 4th ACK, it
doesn't seem to be useful, except when IDs are known in advance via
another channel. Better not to break that.
- Now, combining both an MP_CAPABLE and an MP_JOIN will no longer
result to a reject of the two options, but only the second suboption
is ignored. That seems OK to do that for this unexpected error. At
least now all inconsistent combinations are handled the same way.
This could change later in next. This also means the explicit checks
for having both MPC + MPJ in subflow.c will now be unreachable.
That's fine, they will be removed in a follow-up patch.
- In case of conflicting combinations, the extra suboption(s) is/are
ignored: having such combinations either means the remote peer is
buggy, or is evil. The simplest action is then taken in this case:
stop processing the current suboption.
- In mp_opt->suboptions, there is also a bit reserved to the checksum,
which can be used in an MP_CAPABLE and a DSS. Each time a DSS option
can be used in parallel with another option, the checksum can be set,
so the verification is combined into a new OPTIONS_MPTCP_DSS macro.
- An MP_CAPABLE ACK can carry a Data-Level Length, and an optional
Checksum: they are the same as the ones found in a DSS, because a DSS
cannot be used in parallel to an MP_CAPABLE. Similarly, even if there
is room, a DSS cannot be used with an MP_JOIN.
Other Security Trackers
SUSE information
Overall state of this security issue: New
This issue is currently rated as having critical severity.
| CVSS detail | CNA (NVD) | Linux Kernel CNA |
|---|---|---|
| Base Score | 9.8 | 9.8 |
| Vector | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
| Attack Vector | Network | Network |
| Attack Complexity | Low | Low |
| Privileges Required | None | None |
| User Interaction | None | None |
| Scope | Unchanged | Unchanged |
| Confidentiality Impact | High | High |
| Integrity Impact | High | High |
| Availability Impact | High | High |
| CVSSv3 Version | 3.1 | 3.1 |
Note from the SUSE Security Team on the kernel-default package
SUSE will no longer fix all CVEs in the Linux Kernel anymore, but declare some bug classes as won't fix. Please refer to TID 21496 for more details. No SUSE Bugzilla entries cross referenced. No SUSE Security Announcements cross referenced.Status of this issue by product and package
Please note that this evaluation state might be work in progress, incomplete or outdated. Also information for service packs in the LTSS phase is only included for issues meeting the LTSS criteria. If in doubt, feel free to contact us for clarification. The updates are grouped by state of their lifecycle. SUSE product lifecycles are documented on the lifecycle page.
| Product(s) | Source package | State |
|---|---|---|
| Products under general support and receiving all security fixes. | ||
| SUSE Linux Enterprise Desktop 15 SP7 | kernel-default | Analysis |
| SUSE Linux Enterprise Desktop 15 SP7 | kernel-source | Analysis |
| SUSE Linux Enterprise High Availability Extension 15 SP7 | kernel-default | Analysis |
| SUSE Linux Enterprise High Availability Extension 15 SP7 | kernel-source | Analysis |
| SUSE Linux Enterprise High Availability Extension 16.0 | kernel-default | Analysis |
| SUSE Linux Enterprise High Availability Extension 16.0 | kernel-source | Analysis |
| SUSE Linux Enterprise High Availability Extension 16.1 | kernel-default | Analysis |
| SUSE Linux Enterprise High Availability Extension 16.1 | kernel-source | Analysis |
| SUSE Linux Enterprise Micro 5.3 | kernel-default | Analysis |
| SUSE Linux Enterprise Micro 5.3 | kernel-rt | Analysis |
| SUSE Linux Enterprise Micro 5.3 | kernel-source | Analysis |
| SUSE Linux Enterprise Micro 5.3 | kernel-source-rt | Analysis |
| SUSE Linux Enterprise Micro 5.4 | kernel-default | Analysis |
| SUSE Linux Enterprise Micro 5.4 | kernel-rt | Analysis |
| SUSE Linux Enterprise Micro 5.4 | kernel-source | Analysis |
| SUSE Linux Enterprise Micro 5.4 | kernel-source-rt | Analysis |
| SUSE Linux Enterprise Micro 5.5 | kernel-default | Analysis |
| SUSE Linux Enterprise Micro 5.5 | kernel-source | Analysis |
| SUSE Linux Enterprise Micro 5.5 | kernel-source-rt | Analysis |
| SUSE Linux Enterprise Module for Basesystem 15 SP7 | kernel-default | Analysis |
| SUSE Linux Enterprise Module for Basesystem 15 SP7 | kernel-source | Analysis |
| SUSE Linux Enterprise Module for Development Tools 15 SP7 | kernel-default | Analysis |
| SUSE Linux Enterprise Module for Development Tools 15 SP7 | kernel-source | Analysis |
| SUSE Linux Enterprise Real Time 15 SP7 | kernel-source-rt | Analysis |
| SUSE Linux Enterprise Server 15 SP7 | kernel-default | Analysis |
| SUSE Linux Enterprise Server 15 SP7 | kernel-source | Analysis |
| SUSE Linux Enterprise Server 16.0 | kernel-default | Analysis |
| SUSE Linux Enterprise Server 16.0 | kernel-source | Analysis |
| SUSE Linux Enterprise Server 16.1 | kernel-default | Analysis |
| SUSE Linux Enterprise Server 16.1 | kernel-source | Analysis |
| SUSE Linux Enterprise Server for SAP Applications 15 SP7 | kernel-default | Analysis |
| SUSE Linux Enterprise Server for SAP Applications 15 SP7 | kernel-source | Analysis |
| SUSE Linux Enterprise Server for SAP applications 16.0 | kernel-default | Analysis |
| SUSE Linux Enterprise Server for SAP applications 16.0 | kernel-source | Analysis |
| SUSE Linux Enterprise Server for SAP applications 16.1 | kernel-default | Analysis |
| SUSE Linux Enterprise Server for SAP applications 16.1 | kernel-source | Analysis |
| SUSE Linux Enterprise Workstation Extension 15 SP7 | kernel-default | Analysis |
| SUSE Linux Enterprise Workstation Extension 15 SP7 | kernel-source | Analysis |
| SUSE Linux Micro 6.0 | kernel-default | Analysis |
| SUSE Linux Micro 6.0 | kernel-source | Analysis |
| SUSE Linux Micro 6.0 | kernel-source-rt | Analysis |
| SUSE Linux Micro 6.1 | kernel-default | Analysis |
| SUSE Linux Micro 6.1 | kernel-source | Analysis |
| SUSE Linux Micro 6.1 | kernel-source-rt | Analysis |
| SUSE Linux Micro 6.2 | kernel-default | Analysis |
| SUSE Linux Micro 6.2 | kernel-source | Analysis |
| SUSE Linux Micro Extras 6.0 | kernel-default | Analysis |
| SUSE Linux Micro Extras 6.0 | kernel-source | Analysis |
| SUSE Linux Micro Extras 6.0 | kernel-source-rt | Analysis |
| SUSE Linux Micro Extras 6.1 | kernel-default | Analysis |
| SUSE Linux Micro Extras 6.1 | kernel-source | Analysis |
| SUSE Real Time Module 15 SP7 | kernel-source-rt | Analysis |
| openSUSE Leap 16.0 | kernel-source | Analysis |
| Products under Long Term Service Pack support and receiving important and critical security fixes. | ||
| SUSE Linux Enterprise High Performance Computing 12 SP5 | kernel-source | Analysis |
| SUSE Linux Enterprise High Performance Computing 15 SP4-LTSS | kernel-default | Analysis |
| SUSE Linux Enterprise High Performance Computing 15 SP4-LTSS | kernel-source | Analysis |
| SUSE Linux Enterprise High Performance Computing 15 SP5 | kernel-source | Analysis |
| SUSE Linux Enterprise High Performance Computing 15 SP5-LTSS | kernel-default | Analysis |
| SUSE Linux Enterprise High Performance Computing 15 SP5-LTSS | kernel-source | Analysis |
| SUSE Linux Enterprise Module for Basesystem 15 SP4 | kernel-source | Analysis |
| SUSE Linux Enterprise Module for Basesystem 15 SP5 | kernel-source | Analysis |
| SUSE Linux Enterprise Module for Basesystem 15 SP6 | kernel-source | Analysis |
| SUSE Linux Enterprise Module for Development Tools 15 SP4 | kernel-source | Analysis |
| SUSE Linux Enterprise Module for Development Tools 15 SP5 | kernel-source | Analysis |
| SUSE Linux Enterprise Module for Development Tools 15 SP6 | kernel-source | Analysis |
| SUSE Linux Enterprise Server 11 SP4 LTSS EXTREME CORE | kernel-default | Analysis |
| SUSE Linux Enterprise Server 11 SP4 LTSS EXTREME CORE | kernel-source | Analysis |
| SUSE Linux Enterprise Server 12 SP5 | kernel-source | Analysis |
| SUSE Linux Enterprise Server 12 SP5-LTSS | kernel-default | Analysis |
| SUSE Linux Enterprise Server 12 SP5-LTSS | kernel-source | Analysis |
| SUSE Linux Enterprise Server 15 SP4 | kernel-source | Analysis |
| SUSE Linux Enterprise Server 15 SP4-LTSS | kernel-default | Analysis |
| SUSE Linux Enterprise Server 15 SP4-LTSS | kernel-source | Analysis |
| SUSE Linux Enterprise Server 15 SP5 | kernel-source | Analysis |
| SUSE Linux Enterprise Server 15 SP5-LTSS | kernel-default | Analysis |
| SUSE Linux Enterprise Server 15 SP5-LTSS | kernel-source | Analysis |
| SUSE Linux Enterprise Server 15 SP6 | kernel-source | Analysis |
| SUSE Linux Enterprise Server 15 SP6-LTSS | kernel-default | Analysis |
| SUSE Linux Enterprise Server 15 SP6-LTSS | kernel-source | Analysis |
| SUSE Linux Enterprise Server LTSS Extended Security 12 SP5 | kernel-default | Analysis |
| SUSE Linux Enterprise Server LTSS Extended Security 12 SP5 | kernel-source | Analysis |
| SUSE Linux Enterprise Server for SAP Applications 15 SP4 | kernel-default | Analysis |
| SUSE Linux Enterprise Server for SAP Applications 15 SP4 | kernel-source | Analysis |
| SUSE Linux Enterprise Server for SAP Applications 15 SP5 | kernel-default | Analysis |
| SUSE Linux Enterprise Server for SAP Applications 15 SP5 | kernel-source | Analysis |
| SUSE Linux Enterprise Server for SAP Applications 15 SP6 | kernel-default | Analysis |
| SUSE Linux Enterprise Server for SAP Applications 15 SP6 | kernel-source | Analysis |
| SUSE Manager Proxy 4.3 | kernel-source | Analysis |
| SUSE Manager Proxy LTS 4.3 | kernel-source | Analysis |
| SUSE Manager Retail Branch Server 4.3 | kernel-source | Analysis |
| SUSE Manager Retail Branch Server LTS 4.3 | kernel-source | Analysis |
| SUSE Manager Server 4.3 | kernel-source | Analysis |
| SUSE Manager Server LTS 4.3 | kernel-source | Analysis |
| Products past their end of life and not receiving proactive updates anymore. | ||
| SUSE CaaS Platform 4.0 | kernel-source | Analysis |
| SUSE Enterprise Storage 6 | kernel-source | Analysis |
| SUSE Enterprise Storage 7 | kernel-source | Analysis |
| SUSE Enterprise Storage 7.1 | kernel-source | Analysis |
| SUSE Linux Enterprise Desktop 11 SP4 | kernel-source | Analysis |
| SUSE Linux Enterprise Desktop 15 SP1 | kernel-source | Analysis |
| SUSE Linux Enterprise Desktop 15 SP2 | kernel-source | Analysis |
| SUSE Linux Enterprise Desktop 15 SP3 | kernel-source | Analysis |
| SUSE Linux Enterprise Desktop 15 SP4 | kernel-source | Analysis |
| SUSE Linux Enterprise Desktop 15 SP5 | kernel-source | Analysis |
| SUSE Linux Enterprise Desktop 15 SP6 | kernel-source | Analysis |
| SUSE Linux Enterprise High Performance Computing 15 SP1 | kernel-source | Analysis |
| SUSE Linux Enterprise High Performance Computing 15 SP1-ESPOS | kernel-source | Analysis |
| SUSE Linux Enterprise High Performance Computing 15 SP1-LTSS | kernel-source | Analysis |
| SUSE Linux Enterprise High Performance Computing 15 SP2 | kernel-source | Analysis |
| SUSE Linux Enterprise High Performance Computing 15 SP2-ESPOS | kernel-source | Analysis |
| SUSE Linux Enterprise High Performance Computing 15 SP2-LTSS | kernel-source | Analysis |
| SUSE Linux Enterprise High Performance Computing 15 SP3 | kernel-source | Analysis |
| SUSE Linux Enterprise High Performance Computing 15 SP3-ESPOS | kernel-source | Analysis |
| SUSE Linux Enterprise High Performance Computing 15 SP3-LTSS | kernel-source | Analysis |
| SUSE Linux Enterprise High Performance Computing 15 SP4 | kernel-source | Analysis |
| SUSE Linux Enterprise High Performance Computing 15 SP4-ESPOS | kernel-source | Analysis |
| SUSE Linux Enterprise High Performance Computing 15 SP5-ESPOS | kernel-source | Analysis |
| SUSE Linux Enterprise Micro 5.0 | kernel-default | Analysis |
| SUSE Linux Enterprise Micro 5.1 | kernel-default | Analysis |
| SUSE Linux Enterprise Micro 5.2 | kernel-default | Analysis |
| SUSE Linux Enterprise Micro 5.2 | kernel-source | Analysis |
| SUSE Linux Enterprise Module for Basesystem 15 SP1 | kernel-source | Analysis |
| SUSE Linux Enterprise Module for Basesystem 15 SP2 | kernel-source | Analysis |
| SUSE Linux Enterprise Module for Basesystem 15 SP3 | kernel-source | Analysis |
| SUSE Linux Enterprise Module for Development Tools 15 SP1 | kernel-source | Analysis |
| SUSE Linux Enterprise Module for Development Tools 15 SP2 | kernel-source | Analysis |
| SUSE Linux Enterprise Module for Development Tools 15 SP3 | kernel-source | Analysis |
| SUSE Linux Enterprise Real Time 15 SP2 | kernel-source | Analysis |
| SUSE Linux Enterprise Real Time 15 SP3 | kernel-source | Analysis |
| SUSE Linux Enterprise Real Time 15 SP4 | kernel-source | Analysis |
| SUSE Linux Enterprise Real Time 15 SP4 | kernel-source-rt | Analysis |
| SUSE Linux Enterprise Real Time 15 SP5 | kernel-source-rt | Analysis |
| SUSE Linux Enterprise Server 11 SP4 | kernel-source | Analysis |
| SUSE Linux Enterprise Server 11 SP4-LTSS | kernel-source | Analysis |
| SUSE Linux Enterprise Server 15 SP1 | kernel-source | Analysis |
| SUSE Linux Enterprise Server 15 SP1-BCL | kernel-source | Analysis |
| SUSE Linux Enterprise Server 15 SP1-LTSS | kernel-default | Analysis |
| SUSE Linux Enterprise Server 15 SP1-LTSS | kernel-source | Analysis |
| SUSE Linux Enterprise Server 15 SP2 | kernel-source | Analysis |
| SUSE Linux Enterprise Server 15 SP2-BCL | kernel-source | Analysis |
| SUSE Linux Enterprise Server 15 SP2-LTSS | kernel-default | Analysis |
| SUSE Linux Enterprise Server 15 SP2-LTSS | kernel-source | Analysis |
| SUSE Linux Enterprise Server 15 SP3 | kernel-source | Analysis |
| SUSE Linux Enterprise Server 15 SP3-BCL | kernel-source | Analysis |
| SUSE Linux Enterprise Server 15 SP3-LTSS | kernel-default | Analysis |
| SUSE Linux Enterprise Server 15 SP3-LTSS | kernel-source | Analysis |
| SUSE Linux Enterprise Server for SAP Applications 15 SP1 | kernel-source | Analysis |
| SUSE Linux Enterprise Server for SAP Applications 15 SP2 | kernel-source | Analysis |
| SUSE Linux Enterprise Server for SAP Applications 15 SP3 | kernel-source | Analysis |
| SUSE Manager Proxy 4.0 | kernel-source | Analysis |
| SUSE Manager Proxy 4.1 | kernel-source | Analysis |
| SUSE Manager Proxy 4.2 | kernel-source | Analysis |
| SUSE Manager Retail Branch Server 4.0 | kernel-source | Analysis |
| SUSE Manager Retail Branch Server 4.1 | kernel-source | Analysis |
| SUSE Manager Retail Branch Server 4.2 | kernel-source | Analysis |
| SUSE Manager Server 4.0 | kernel-source | Analysis |
| SUSE Manager Server 4.1 | kernel-source | Analysis |
| SUSE Manager Server 4.2 | kernel-source | Analysis |
| SUSE Real Time Module 15 SP4 | kernel-source-rt | Analysis |
| SUSE Real Time Module 15 SP5 | kernel-source-rt | Analysis |
| openSUSE Leap 15.3 | kernel-source | Analysis |
| openSUSE Leap 15.4 | kernel-source | Analysis |
| openSUSE Leap 15.4 | kernel-source-rt | Analysis |
| openSUSE Leap 15.5 | kernel-source | Analysis |
| openSUSE Leap 15.5 | kernel-source-rt | Analysis |
| openSUSE Leap 15.6 | kernel-source | Analysis |
SUSE Timeline for this CVE
CVE page created: Wed Aug 26 21:56:54 2026CVE page last modified: Fri Aug 28 20:11:16 2026