Skip to content
Noroxi
NVD / CVE Program· CNA Linux

CVE-2026-46086: net: bridge: use a stable FDB dst snapshot in RCU readers

Noroxi assessment

Priority: Monitor (action score 22/100)

  • 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: 0.12% (FIRST EPSS).
  • Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: Linux Linux 0b9e4bbfb7c949151e3acd44ed4aa33614d2e110, 1406c4e0ed1eaf8a29801ab1163d00fb7ee4359a, 5424e678f9b304e148cf5dcc047cffc7a56a3bb5; azl3 kernel 6.6.139.1-1 on Azure Linux 3.0 6.6.141.1-1.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 0b9e4bbfb7c949151e3acd44ed4aa33614d2e110, 1406c4e0ed1eaf8a29801ab1163d00fb7ee4359a, 5424e678f9b304e148cf5dcc047cffc7a56a3bb5; azl3 kernel 6.6.139.1-1 on Azure Linux 3.0 6.6.141.1-1 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: use a stable FDB dst snapshot in RCU readers Local FDB entries can be rewritten in place by `fdb_delete_local()`, which updates `f->dst` to another port or to `NULL` while keeping the entry alive. Several bridge RCU readers inspect `f->dst`, including `br_fdb_fillbuf()` through the `brforward_read()` sysfs path. These readers currently load `f->dst` multiple times and can therefore observe inconsistent values across the check and later dereference. In `br_fdb_fillbuf()`, this means a concurrent local-FDB update can change `f->dst` after the NULL check and before the `port_no` dereference, leading to a NULL-ptr-deref. Fix this by taking a single `READ_ONCE()` snapshot of `f->dst` in each affected RCU reader and using that snapshot for the rest of the access sequence. Also publish the in-place `f->dst` updates in `fdb_delete_local()` with `WRITE_ONCE()` so the readers and writer use matching access patterns.

MediumCVSS 5.5 · v3.1—No exploit Fix available
Published
May 27, 2026
Updated
Oct 15, 2026
EPSS
0.1% · 2th percentile

Report tools

JSON

Action score

22

Monitor

Low priority for now.

CVSS
22 / 40 · 5.5 / 10
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

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2026-46086

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

One daily email digest (06:00 UTC); connect a webhook for KEV listings and weaponized exploits instantly.

Your free account also gets you

Running WordPress? Scan your site free with WP Lens

  • Stack alerts: add the products and versions you run, get the new CVEs that affect them
  • Uptime monitoring: 1 site, instant email when it goes down
  • Add your domain: subdomains and takeover risk scanned every week (1 domain)
  • 10 scans an hour on the security tools (3 a day without an account), an API key and MCP
  • All your scans in one panel: findings, what changed in the last scan, a report per domain or per client (PDF, share link)
All free tools

Sign up with email · Have an account? Sign in

Free account, no card. Unfollow any time.

Don't want an account? Get "Exploited this week" by email every MondayDon't want an account? RSS feed for linux records

Running WordPress? Scan your site free with WP Lens

Is your version affected? Check it

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 help

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.

VendorProduct
linuxlinux kernel

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • linux linux kernel3.14.1 and later · before 5.10.259
  • linux linux kernel5.11 and later · before 5.15.210
  • linux linux kernel5.16 and later · before 6.1.176
  • linux linux kernel6.2 and later · before 6.6.140
  • linux linux kernel6.7 and later · before 6.12.86
  • linux linux kernel6.13 and later · before 6.18.27
  • linux linux kernel6.19 and later · before 7.0.4
  • linux linux kernel3.14

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

    • 3.14affected
    • 960b589f86c74ce582922fcb996103271081f4de and later · before c502fa9f094cb03d1d1685c71e2105ab359bc2b8affected · git
    • 960b589f86c74ce582922fcb996103271081f4de and later · before a6ae4511c07b91f597e461406c6330f0d4ff810eaffected · git
    • 960b589f86c74ce582922fcb996103271081f4de and later · before 1406c4e0ed1eaf8a29801ab1163d00fb7ee4359aaffected · git
    • 960b589f86c74ce582922fcb996103271081f4de and later · before 0b9e4bbfb7c949151e3acd44ed4aa33614d2e110affected · git
    • 960b589f86c74ce582922fcb996103271081f4de and later · before 81af4137a30c4c2dc694dea8cacb180bd66000efaffected · git
    • 960b589f86c74ce582922fcb996103271081f4de and later · before 5424e678f9b304e148cf5dcc047cffc7a56a3bb5affected · git
    • 960b589f86c74ce582922fcb996103271081f4de and later · before 9a2d9d4e657b23dc21f24cf139e3aeff0b61341faffected · git
    • 960b589f86c74ce582922fcb996103271081f4de and later · before df4601653201de21b487c3e7fffd464790cab808affected · git
    • before 3.14not affected · semver

Package-level exposure

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

EcosystemPackageAffected rangeFix
AlmaLinux:10kernelbefore 6.12.0-211.40.1.el10_26.12.0-211.40.1.el10_2
AlmaLinux:10kernel-64kbefore 6.12.0-211.40.1.el10_26.12.0-211.40.1.el10_2
AlmaLinux:10kernel-64k-corebefore 6.12.0-211.40.1.el10_26.12.0-211.40.1.el10_2
AlmaLinux:10kernel-64k-debugbefore 6.12.0-211.40.1.el10_26.12.0-211.40.1.el10_2
AlmaLinux:10kernel-64k-debug-corebefore 6.12.0-211.40.1.el10_26.12.0-211.40.1.el10_2
AlmaLinux:10kernel-64k-debug-develbefore 6.12.0-211.40.1.el10_26.12.0-211.40.1.el10_2
AlmaLinux:10kernel-64k-debug-devel-matchedbefore 6.12.0-211.40.1.el10_26.12.0-211.40.1.el10_2
AlmaLinux:10kernel-64k-debug-modulesbefore 6.12.0-211.40.1.el10_26.12.0-211.40.1.el10_2
AlmaLinux:10kernel-64k-debug-modules-corebefore 6.12.0-211.40.1.el10_26.12.0-211.40.1.el10_2
AlmaLinux:10kernel-64k-debug-modules-extrabefore 6.12.0-211.40.1.el10_26.12.0-211.40.1.el10_2
AlmaLinux:10kernel-64k-develbefore 6.12.0-211.40.1.el10_26.12.0-211.40.1.el10_2
AlmaLinux:10kernel-64k-devel-matchedbefore 6.12.0-211.40.1.el10_26.12.0-211.40.1.el10_2
AlmaLinux:10kernel-64k-modulesbefore 6.12.0-211.40.1.el10_26.12.0-211.40.1.el10_2
AlmaLinux:10kernel-64k-modules-corebefore 6.12.0-211.40.1.el10_26.12.0-211.40.1.el10_2
AlmaLinux:10kernel-64k-modules-extrabefore 6.12.0-211.40.1.el10_26.12.0-211.40.1.el10_2
AlmaLinux:10kernel-abi-stablelistsbefore 6.12.0-211.40.1.el10_26.12.0-211.40.1.el10_2
AlmaLinux:10kernel-corebefore 6.12.0-211.40.1.el10_26.12.0-211.40.1.el10_2
AlmaLinux:10kernel-cross-headersbefore 6.12.0-211.40.1.el10_26.12.0-211.40.1.el10_2
AlmaLinux:10kernel-debugbefore 6.12.0-211.40.1.el10_26.12.0-211.40.1.el10_2
AlmaLinux:10kernel-debug-corebefore 6.12.0-211.40.1.el10_26.12.0-211.40.1.el10_2
AlmaLinux:10kernel-debug-develbefore 6.12.0-211.40.1.el10_26.12.0-211.40.1.el10_2
AlmaLinux:10kernel-debug-devel-matchedbefore 6.12.0-211.40.1.el10_26.12.0-211.40.1.el10_2
AlmaLinux:10kernel-debug-modulesbefore 6.12.0-211.40.1.el10_26.12.0-211.40.1.el10_2
AlmaLinux:10kernel-debug-modules-corebefore 6.12.0-211.40.1.el10_26.12.0-211.40.1.el10_2

+96

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-31431crypto: algif_aead - Revert to operating out-of-placeKEV
    90Now
  • CVE-2022-0847A flaw was found in the way the "flags" member of the new pipe buffer structure was lacking proper initialization in copy_page_to_iter_pipe KEV
    89Now
  • CVE-2021-22555Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACEKEV
    85Now

Published before and after this one in the same product

  • ← EarlierCVE-2026-46078May 27, 2026 · erofs: fix the out-of-bounds nameoff handling for trailing dirents
    28Monitor
  • ← EarlierCVE-2026-46083May 27, 2026 · spi: fix resource leaks on device setup failure
    22Monitor
  • Later →CVE-2026-46088May 27, 2026 · ALSA: control: Validate buf_len before strnlen() in snd_ctl_elem_init_enum_names()
    22Monitor

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 Linux0b9e4bbfb7c949151e3acd44ed4aa33614d2e110Vendor (CNA)
Linux Linux1406c4e0ed1eaf8a29801ab1163d00fb7ee4359aVendor (CNA)
Linux Linux5424e678f9b304e148cf5dcc047cffc7a56a3bb5Vendor (CNA)
Linux Linux81af4137a30c4c2dc694dea8cacb180bd66000efVendor (CNA)
Linux Linux9a2d9d4e657b23dc21f24cf139e3aeff0b61341fVendor (CNA)
Linux Linuxa6ae4511c07b91f597e461406c6330f0d4ff810eVendor (CNA)
Linux Linuxc502fa9f094cb03d1d1685c71e2105ab359bc2b8Vendor (CNA)
Linux Linuxdf4601653201de21b487c3e7fffd464790cab808Vendor (CNA)
azl3 kernel 6.6.139.1-1 on Azure Linux 3.06.6.141.1-1 · CBL-Mariner ReleasesMicrosoft (MSRC)
almalinux:kernel5.14.0-687.25.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k5.14.0-687.25.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-core5.14.0-687.25.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-debug5.14.0-687.25.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-debug-core5.14.0-687.25.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-debug-devel5.14.0-687.25.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-debug-devel-matched5.14.0-687.25.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-debug-modules5.14.0-687.25.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-debug-modules-core5.14.0-687.25.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-debug-modules-extra5.14.0-687.25.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-devel5.14.0-687.25.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-devel-matched5.14.0-687.25.1.el9_8 · AlmaLinux:9Package registry (OSV)
debian:linux6.1.176-1 · Debian:12Package registry (OSV)
red hat:kernel-64k-debug-debuginfo0:5.14.0-687.25.1.el9_8 · Red Hat:enterprise_linux:9::appstreamPackage registry (OSV)
red hat:kernel-64k-debug-devel0:5.14.0-687.25.1.el9_8 · Red Hat:enterprise_linux:9::appstreamPackage registry (OSV)
red hat:kernel-64k-debug-devel-matched0:5.14.0-687.25.1.el9_8 · Red Hat:enterprise_linux:9::appstreamPackage registry (OSV)
red hat:kernel-64k-debuginfo0:5.14.0-687.25.1.el9_8 · Red Hat:enterprise_linux:9::appstreamPackage registry (OSV)
red hat:kernel-64k-devel0:5.14.0-687.25.1.el9_8 · Red Hat:enterprise_linux:9::appstreamPackage registry (OSV)
red hat:kernel-64k-devel-matched0:5.14.0-687.25.1.el9_8 · Red Hat:enterprise_linux:9::appstreamPackage registry (OSV)
red hat:kernel-debug-debuginfo0:5.14.0-687.25.1.el9_8 · Red Hat:enterprise_linux:9::appstreamPackage registry (OSV)
red hat:kernel-debug-devel0:5.14.0-687.25.1.el9_8 · Red Hat:enterprise_linux:9::appstreamPackage registry (OSV)

+6

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

Attack conditions

  • Someone with local access to the system can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
none
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

CWE-476 · NULL Pointer Dereference

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

nvd-primary

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 (10 more)

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

All records