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CVE.org (no NVD analysis yet)· CNA Linux

CVE-2026-100081: xen-netback: defer xenvif_mcast_addr_list_free()

HighCVSS 7.8 · v3.1—No exploit Fix available

Noroxi assessment

Priority: Monitor (action score 31/100)

  • 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: 0.16% (FIRST EPSS).
  • Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. Special conditions such as timing or configuration are required.
  • Fixed version: Linux Linux 0d515c409033c8e2a645a781be3ca76ab825fc8c, 0e786123e46d08d2247ce93a5435e45ed9f4c5d1, 34f0f63dc6dc11895a17bb5672451b6b11622c99; azl3 kernel 6.6.161.1-1 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 0d515c409033c8e2a645a781be3ca76ab825fc8c, 0e786123e46d08d2247ce93a5435e45ed9f4c5d1, 34f0f63dc6dc11895a17bb5672451b6b11622c99; azl3 kernel 6.6.161.1-1 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

Primary sources: NVD · CVE.org · FIRST EPSS

In the Linux kernel, the following vulnerability has been resolved: xen-netback: defer xenvif_mcast_addr_list_free() In order for the function to legitimately avoid locking/RCU, it needs to run after all TX/RX processing has finished/stopped: Lookups happen from xenvif_start_xmit(), while adds/removes happen from xenvif_tx_action() (called out of xenvif_poll()). Move the call out of xenvif_disconnect_data() (the call to the function from connect()'s error path doesn't require any cleaning up there), and put it past the synchronization point in backend_disconnect(). This is XSA-527 / CVE-2026-100081.

Published
Nov 6, 2026
Updated
Nov 10, 2026
EPSS
0.1% · 6th percentile
CWE
—

Report tools

JSON

Action score

31

Monitor

Low priority for now.

CVSS
31 / 40 · 7.8 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

CNA vs NVD score

NVD
—
CNA · Linux
7.8
NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

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-2026-100081

When you'll hear from us

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

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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

    • 4.11affected
    • b17075d5c1988b83f840d272c795ac17d57ce804 and later · before 96e05a8ce243e2207704e2e7a6e7d1172730f515affected · git
    • b17075d5c1988b83f840d272c795ac17d57ce804 and later · before 0e786123e46d08d2247ce93a5435e45ed9f4c5d1affected · git
    • b17075d5c1988b83f840d272c795ac17d57ce804 and later · before 990d123d9eaa3ac6c979eed245658676d65ce0dbaffected · git
    • b17075d5c1988b83f840d272c795ac17d57ce804 and later · before 0d515c409033c8e2a645a781be3ca76ab825fc8caffected · git
    • b17075d5c1988b83f840d272c795ac17d57ce804 and later · before a6bb2f1fa62c56279bdcdadce28d1310c5e12b62affected · git
    • b17075d5c1988b83f840d272c795ac17d57ce804 and later · before 34f0f63dc6dc11895a17bb5672451b6b11622c99affected · git
    • b17075d5c1988b83f840d272c795ac17d57ce804 and later · before fb38fc58acb26d74fe8f7b19621fafaae3c040ffaffected · git
    • before 4.11not affected · semver
    • 5.10.274 and later · up to and including 5.10.*not affected · semver

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12linuxfrom 0—
Debian:13linuxbefore 6.12.116-16.12.116-1

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-2026-99270Nov 3, 2026 · tcp: Fix potential UAF in reqsk_timer_handler().
    32Monitor
  • ← EarlierCVE-2026-100080Nov 6, 2026 · xen-netback: Fix UAF when reading statistics data
    0Monitor
  • Later →CVE-2026-100082Nov 6, 2026 · xen-blkback: Avoid UAF when reading I/O statistics
    0Monitor

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 Linux0d515c409033c8e2a645a781be3ca76ab825fc8cVendor (CNA)
Linux Linux0e786123e46d08d2247ce93a5435e45ed9f4c5d1Vendor (CNA)
Linux Linux34f0f63dc6dc11895a17bb5672451b6b11622c99Vendor (CNA)
Linux Linux96e05a8ce243e2207704e2e7a6e7d1172730f515Vendor (CNA)
Linux Linux990d123d9eaa3ac6c979eed245658676d65ce0dbVendor (CNA)
Linux Linuxa6bb2f1fa62c56279bdcdadce28d1310c5e12b62Vendor (CNA)
Linux Linuxfb38fc58acb26d74fe8f7b19621fafaae3c040ffVendor (CNA)
azl3 kernel 6.6.161.1-1 on Azure Linux 3.0Release NotesMicrosoft (MSRC)
debian:linux6.12.116-1 · Debian:13Package 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.

  1. Published
  2. Fix recordedsame day
  3. TodayNov 13, 2026+7 d
EPSS, last 120 days

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

National notice (Türkiye Cybersecurity Directorate / USOM)

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

All national notices →

Not on record for this CVE: patch commit or PR link · researcher credit · variant or chain candidate · public bounty program.

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.
  • Special conditions such as timing or configuration are required.

If successful

Confidentiality
high · data can be read
Integrity
high · data or configuration can be modified
Availability
high · the service can be disrupted

Impact can extend beyond the vulnerable component (scope changes).

Attack vector
Local
Attack complexity
High
Privileges required
Low
User interaction
None
Scope
Changed
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

—

CVSS vector

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

nvd-secondary

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. CVSS— → 7.8
  2. Severity— → high
  3. Exploit maturity— → none
  4. Fix✗ → ✓

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

References

Show all references (8 more)

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

All records