net: bridge: use option bits for CFM/MRP frame handlers
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: 0.20% (FIRST EPSS).
- Fixed version: Linux Linux 42e033c8f30fd2923ccac3373ae70797e521dae1, 7a49e6b16f36b8e085521699adbca3e321b6dd0c, 994fd705ca498223d188024cde833739a9dddbd2; azl3 kernel 6.6.157.1-1 on Azure Linux 3.0 Release Notes.
- Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).
Low priority for now. Upgrade to Linux Linux 42e033c8f30fd2923ccac3373ae70797e521dae1, 7a49e6b16f36b8e085521699adbca3e321b6dd0c, 994fd705ca498223d188024cde833739a9dddbd2; azl3 kernel 6.6.157.1-1 on Azure Linux 3.0 Release Notes 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
In the Linux kernel, the following vulnerability has been resolved: net: bridge: use option bits for CFM/MRP frame handlers CFM and MRP register a global br_frame_type whose hlist_node is linked into the per-bridge frame_type_list when the first MEP/MRP instance is created. Enabling the protocol on multiple bridges therefore inserts the same node into multiple lists. Unregistering it on one bridge then corrupts list state belonging to another. These handlers can only be installed once per bridge, and they are uncommon. Track their per-bridge enable state with net_bridge option bits, which already live on the Rx hot cache line, and dispatch the matching handler directly from the receive path. Check both bits together first as an unlikely case. Remove the generic frame_type_list and br_frame_type helpers, which have had no other users since CFM and MRP were added. That shrinks struct net_bridge by 8 bytes and drops the list walk from the fast path. When neither protocol is compiled in, BR_CFM_MRP_OPTS is 0 and the compiler prunes the branch.
- Published
- Sep 25, 2026
- Updated
- Oct 3, 2026
- EPSS
- 0.2% · 9th percentile
- CWE
- —
Report tools
Action score
0
Monitor
Low priority for now.
- CVSS
- 0 / 40 · —
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.2%
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
If any of these changes, we'll tell you in the daily email digest.
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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.
We use this product, ask for helpAffected 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.
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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
- 5.11affected
- 90c628dd47ff4178f645b34938470bf43d02d123 and later · before be5ead6552418d70df3a76b962ccd6ed78a31fb5affected · git
- 90c628dd47ff4178f645b34938470bf43d02d123 and later · before 994fd705ca498223d188024cde833739a9dddbd2affected · git
- 90c628dd47ff4178f645b34938470bf43d02d123 and later · before 42e033c8f30fd2923ccac3373ae70797e521dae1affected · git
- 90c628dd47ff4178f645b34938470bf43d02d123 and later · before 7a49e6b16f36b8e085521699adbca3e321b6dd0caffected · git
- before 5.11not affected · semver
- 6.12.112 and later · up to and including 6.12.*not affected · semver
- 6.18.53 and later · up to and including 6.18.*not affected · semver
- 7.2.7 and later · up to and including 7.2.*not affected · semver
- 7.3-rc3 and laternot affected · original_commit_for_fix
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Debian:12 | linux | all versions | — |
| Debian:14 | linux | before 7.2.7-1 | 7.2.7-1 |
Same product
linux: all recordsOther highest-scoring records for the same primary product.
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Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| Linux Linux | 42e033c8f30fd2923ccac3373ae70797e521dae1 | Vendor (CNA) |
| Linux Linux | 7a49e6b16f36b8e085521699adbca3e321b6dd0c | Vendor (CNA) |
| Linux Linux | 994fd705ca498223d188024cde833739a9dddbd2 | Vendor (CNA) |
| Linux Linux | be5ead6552418d70df3a76b962ccd6ed78a31fb5 | Vendor (CNA) |
| azl3 kernel 6.6.157.1-1 on Azure Linux 3.0 | Release Notes | Microsoft (MSRC) |
| debian:linux | 7.2.7-1 · Debian:14 | Package 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.
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 researchersFinders, 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.
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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.
- TR-26-1184 · Sep 28, 2026(Linux Kernel Güvenlik Bildirimi)
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
- Fix✗ → ✓
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References
Show all references (3 more)Show less
Vendor advisories and official records. Exploit/PoC links are deliberately left out.