medium 5.5

CVE-2026-53245 json

net/802/mrp: fix vector attribute parsing in mrp_pdu_parse_vecattr

published 2026-06-25 4 mo ago modified 2026-11-06 2 d ago also EUVD-2026-39196

cvss: 5.5; version 3.1, NVD
cisa kev: Not listed; not in CISA's catalog
epss: 0.1%; EPSS 0.1% chance of exploitation in 30 days, percentile 2%
public exploits: 0; none known

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

In mrp_pdu_parse_vecattr(), vector attribute events are encoded three per byte and valen tracks the number of events left to process.

The parser decrements valen after processing the first and second events from each event byte, but not after processing the third one. When valen is exactly a multiple of three, the loop continues after the last valid event and consumes the next byte as a new event byte, applying a spurious event to the MRP applicant state.

Additionally, when valen is zero the parser unconditionally consumes attrlen bytes as FirstValue and advances the offset, even though per IEEE 802.1ak a VectorAttribute with only a LeaveAllEvent has valen of zero and no FirstValue or Vector fields. This corrupts the offset for subsequent PDU parsing.

Also, when valen exceeds three the loop crosses byte boundaries but the attribute value is not incremented between the last event of one byte and the first event of the next. This causes the first event of the next byte to use the same attribute value as the third event rather than the next consecutive value.

Decrement valen after processing the third event, skip FirstValue consumption when valen is zero, and increment the attribute value at the end of each loop iteration.

Patch / fix

fixed in 1 distros 5 links 8

Linux Linux 5.10.259, 5.15.210, 6.1.176, 6.6.143, 6.12.94, 6.18.36, 7.0.13, 7.1

debian ubuntu suse opensuse azure linux

linux Debian 12 6.1.176-1
linux Debian 13 6.12.94-1
linux Debian 14 7.0.13-1

debian advisories DEBIAN-CVE-2026-53245

linux Ubuntu 22.04 LTS 5.15.0-198.208
linux Ubuntu 24.04 LTS 6.8.0-146.146
linux Ubuntu 26.04 LTS 7.0.0-31.31
linux-aws Ubuntu 22.04 LTS 5.15.0-1117.124
linux-aws Ubuntu 24.04 LTS 6.8.0-1066.69
linux-aws Ubuntu 26.04 LTS 7.0.0-1012.12
linux-gcp Ubuntu 22.04 LTS 5.15.0-1118.128
linux-gcp Ubuntu 24.04 LTS 6.8.0-1070.78

ubuntu advisories UBUNTU-CVE-2026-53245

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-default SLES 16.0, SLE High Availability Extension 16.0, Linux Micro 6.2 +1 more 6.12.0-160000.37.1
kernel-rt Linux Micro 6.2 6.12.0-160000.37.1
kernel-64kb SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 6.12.0-160000.37.1
kernel-source SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 6.12.0-160000.37.1
kernel-default-base SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 6.12.0-160000.37.1.160000.2.19
kernel-syms SLES 16.0, Linux Micro Extras 6.2, SLES for SAP applications 16.0 6.12.0-160000.37.1
kernel-azure SLES 16.0, SLES for SAP applications 16.0 6.12.0-160000.37.1
kernel-obs-qa SLES 16.0, SLES for SAP applications 16.0 6.12.0-160000.37.1

suse advisories SUSE-SU-2026:3594-1 SUSE-SU-2026:23237-1 SUSE-SU-2026:23068-1 SUSE-SU-2026:23221-1 SUSE-SU-2026:23231-1 SUSE-SU-2026:23066-1

kernel-rt openSUSE Leap 16.0 6.12.0-160000.37.1
dtb-aarch64 openSUSE Leap 16.0 6.12.0-160000.37.1
kernel-64kb openSUSE Leap 16.0 6.12.0-160000.37.1
kernel-syms openSUSE Leap 16.0 6.12.0-160000.37.1
kernel-azure openSUSE Leap 16.0 6.12.0-160000.37.1
kernel-obs-qa openSUSE Leap 16.0 6.12.0-160000.37.1
kernel-source openSUSE Leap 16.0 6.12.0-160000.37.1
kernel-default openSUSE Leap 16.0 6.12.0-160000.37.1

opensuse advisories openSUSE-SU-2026:21555-1

kernel Azure Linux 3.0 6.6.143.1-1

azure linux advisories AZL-90380

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-2026-53245 updated 2026-11-05 cvss 5.5

kernel: net/802/mrp: fix vector attribute parsing in mrp_pdu_parse_vecattr

Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more 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: workaround, no fix available “Fix deferred”
Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 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-26-295-16 updated 2026-10-22 cvss 0.0

Siemens SIMATIC S7-1500 TM MFP

Siemens SIMATIC S7-1500 TM MFP - GNU/Linux subsystem
affected: mitigation, no fix available

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: partial
Assessed: 3 d ago (2026-11-06)

Exploit prediction

0.13% chance of exploitation in the next 30 days, higher than 2% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
NVD	3.1	5.5	CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Affected products

Linux Linux
Siemens SIMATIC S7-1500 TM MFP - GNU/Linux subsystem

Classification

Technology feeds

Linux kernel rss critical rss

References

Sources

CVE List CVE-2026-53245
NVD CVE-2026-53245

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