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NVD / CVE Program· CNA Linux

CVE-2026-74659: net: bridge: mrp: fix uninitialised bytes on the wire

Noroxi assessment

Priority: Monitor (action score 0/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.17% (FIRST EPSS).
  • Fixed version: Linux Linux 014c062d23c63ec77ef2cf17a0d9363c7441cc94, 06d58b8d2f053ced82e01efaeb6e7c82891eed58, 5912cf1822fbe53ae275c147868740eb384a5d3e.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 014c062d23c63ec77ef2cf17a0d9363c7441cc94, 06d58b8d2f053ced82e01efaeb6e7c82891eed58, 5912cf1822fbe53ae275c147868740eb384a5d3e or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

In the Linux kernel, the following vulnerability has been resolved: net: bridge: mrp: fix uninitialised bytes on the wire br_mrp_alloc_test_skb() builds MRP test frames on an skb from dev_alloc_skb(), which does not clear the linear data area. On the MRA ring-role branch the sub-option TLV header is appended with sub_tlv = skb_put(skb, sizeof(*sub_tlv)); sub_tlv->type = BR_MRP_SUB_TLV_HEADER_TEST_AUTO_MGR; so sub_tlv->length is never written, and the two trailing alignment bytes are appended with a bare skb_put() that does not clear them either. The neighbouring oui and sub_opt regions are explicitly zeroed, so three uninitialised bytes are left in every MRA MRP_Test frame that goes out. Put the sub-option TLV header and the alignment padding in a single skb_put_zero(), which clears both. The AUTO_MGR sub-TLV carries no payload, so the zeroed length field is already the value it should have.

—No exploit Fix available
Published
Aug 22, 2026
Updated
Oct 14, 2026
EPSS
0.1% · 6th percentile
CWE
—

Report tools

JSON

Action score

0

Monitor

Low priority for now.

CVSS
0 / 40 · —
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

—

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

  • Linux Linux

    • 5.14affected
    • f7458934b0791c39a001e4d902fc3bf697b439b5 and later · before 014c062d23c63ec77ef2cf17a0d9363c7441cc94affected · git
    • f7458934b0791c39a001e4d902fc3bf697b439b5 and later · before 7ebc23ff03668042e0b0e4034bb1518d36198d9eaffected · git
    • f7458934b0791c39a001e4d902fc3bf697b439b5 and later · before 06d58b8d2f053ced82e01efaeb6e7c82891eed58affected · git
    • f7458934b0791c39a001e4d902fc3bf697b439b5 and later · before a5e385eeb2d6dbbbdebfa050e67c34734ae12693affected · git
    • f7458934b0791c39a001e4d902fc3bf697b439b5 and later · before 5912cf1822fbe53ae275c147868740eb384a5d3eaffected · git
    • f7458934b0791c39a001e4d902fc3bf697b439b5 and later · before e08665218040f8e312abe40f74543186f3c2c941affected · git
    • f7458934b0791c39a001e4d902fc3bf697b439b5 and later · before 63488dba65ef91373ef616575b32eb0eb21459f4affected · git
    • before 5.14not affected · semver
    • 5.15.216 and later · up to and including 5.15.*not affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.187-16.1.187-1
Debian:12linux-6.12before 6.12.107-1~deb12u16.12.107-1~deb12u1
Debian:13linuxbefore 6.12.105-16.12.105-1
Debian:14linuxbefore 7.1.9-17.1.9-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-74705udp: fix potential use-after-free in tunnel segmentation
    40Plan
  • CVE-2026-74612veth: fix skb length accounting after XDP frag adjustment
    40Plan
  • CVE-2026-74475vxlan: use neigh_ha_snapshot() in route_shortcircuit()
    40Plan

Published before and after this one in the same product

  • ← EarlierCVE-2026-74657Aug 22, 2026 · ipv4: Fix fib_nlmsg_size() for RTA_VIA nexthops
    0Monitor
  • ← EarlierCVE-2026-74658Aug 22, 2026 · futex: Prevent robust futex exit race some more
    0Monitor
  • Later →CVE-2026-74660Aug 22, 2026 · netfilter: ebt_nflog: pin the NFLOG backend
    31Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux014c062d23c63ec77ef2cf17a0d9363c7441cc94Vendor (CNA)
Linux Linux06d58b8d2f053ced82e01efaeb6e7c82891eed58Vendor (CNA)
Linux Linux5912cf1822fbe53ae275c147868740eb384a5d3eVendor (CNA)
Linux Linux63488dba65ef91373ef616575b32eb0eb21459f4Vendor (CNA)
Linux Linux7ebc23ff03668042e0b0e4034bb1518d36198d9eVendor (CNA)
Linux Linuxa5e385eeb2d6dbbbdebfa050e67c34734ae12693Vendor (CNA)
Linux Linuxe08665218040f8e312abe40f74543186f3c2c941Vendor (CNA)
debian:linux6.1.187-1 · Debian:12Package registry (OSV)
debian:linux-6.126.12.107-1~deb12u1 · Debian:12Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

All national notices →

Technical details

No CVSS vector for this record, so attack conditions can't be derived.

Weakness class (CWE)

—

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (6 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records