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NVD / CVE Program· CNA Linux

CVE-2026-72444: flow_dissector: check device type before reading ETH_ADDRS

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: 0.12% (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 0fe6455b8e1a22414f39c07bc90a1df12b52ec74, 594c90b197141944f25991b8314de5c26ee27a7e, 825de39f0c35a112148799b3cbe45af3766c018a.

Low priority for now. Upgrade to Linux Linux 0fe6455b8e1a22414f39c07bc90a1df12b52ec74, 594c90b197141944f25991b8314de5c26ee27a7e, 825de39f0c35a112148799b3cbe45af3766c018a 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: flow_dissector: check device type before reading ETH_ADDRS __skb_flow_dissect() unconditionally reads 12 bytes from eth_hdr(skb) when FLOW_DISSECTOR_KEY_ETH_ADDRS is requested. This assumes the skb has a valid Ethernet header at mac_header, which is not always the case. The problem can be triggered by: 1. Creating a TUN device in L3 mode (IFF_TUN, hard_header_len=0) 2. Attaching a multiq qdisc with a flower filter matching on eth_src 3. Sending a packet through AF_PACKET Since TUN in L3 mode has no link-layer header, mac_header points to the L3 data area. The flow dissector reads 12 bytes of uninitialized skb memory, which then propagates through fl_set_masked_key() and is used as a rhashtable lookup key in __fl_lookup(), as reported by KMSAN. Rejecting the filter in the control path (at tc filter add time) is not feasible because TC filter blocks can be shared between arbitrary devices -- a filter installed on an Ethernet device may later classify packets on a headerless device through a shared block. The device association is not fixed at filter creation time. Fix this by gating the memcpy on dev->type == ARPHRD_ETHER, which ensures only true Ethernet-framed packets have their addresses read. This is more precise than the previous hard_header_len >= 12 check, which would incorrectly pass for non-Ethernet link types like IPoIB (ARPHRD_INFINIBAND, hard_header_len=24) and FDDI (hard_header_len=21) whose L2 headers are not in Ethernet format. Additionally check skb_mac_header_was_set() to guard against the pathological case where mac_header is the unset sentinel (~0U), which would cause eth_hdr() to return a wild pointer. For the act_mirred redirect case (Ethernet packet redirected to a non-Ethernet device sharing a TC block), zeroing the key is the correct behavior: the packet is now being classified on the target device, where Ethernet address matching is not semantically meaningful. Note: on non-Ethernet devices, the zeroed key will match a filter configured with all-zero MAC addresses. This is an improvement over the previous behavior where uninitialized memory could randomly match any filter.

HighCVSS 7.8 · v3.1—No exploit Fix available
Published
Aug 15, 2026
Updated
Oct 16, 2026
EPSS
0.1% · 2th 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%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
total

Vulnrichment: CISA's decision-tree inputs.

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

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When you'll hear from us

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  • when exploit code appears or is weaponized
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  • 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

    • 4.2affected
    • 67a900cc0436d74e7ff89042371760def087680d and later · before 0fe6455b8e1a22414f39c07bc90a1df12b52ec74affected · git
    • 67a900cc0436d74e7ff89042371760def087680d and later · before 9a65860959db594dfc1820c7fdc09285fb7556bfaffected · git
    • 67a900cc0436d74e7ff89042371760def087680d and later · before 594c90b197141944f25991b8314de5c26ee27a7eaffected · git
    • 67a900cc0436d74e7ff89042371760def087680d and later · before c6d3bcb0f934d4297ac5fa1c8656ae40694fb601affected · git
    • 67a900cc0436d74e7ff89042371760def087680d and later · before 825de39f0c35a112148799b3cbe45af3766c018aaffected · git
    • 67a900cc0436d74e7ff89042371760def087680d and later · before bf6e8af2c8be77489bedeae9f8a9654cb710e500affected · git
    • before 4.2not affected · semver
    • 6.1.178 and later · up to and including 6.1.*not affected · semver
    • 6.6.145 and later · up to and including 6.6.*not affected · semver

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.180-16.1.180-1
Debian:13linuxbefore 6.12.100-16.12.100-1
Debian:14linuxbefore 7.1.5-17.1.5-1

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-2026-72440Aug 15, 2026 · md/raid1: fix writes_pending and barrier reference leaks on write failures
    28Monitor
  • ← EarlierCVE-2026-72441Aug 15, 2026 · ieee802154: fix kernel-infoleak in dgram_recvmsg()
    0Monitor
  • Later →CVE-2026-72447Aug 15, 2026 · sctp: hold socket lock when dumping endpoints in sctp_diag
    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 Linux0fe6455b8e1a22414f39c07bc90a1df12b52ec74Vendor (CNA)
Linux Linux594c90b197141944f25991b8314de5c26ee27a7eVendor (CNA)
Linux Linux825de39f0c35a112148799b3cbe45af3766c018aVendor (CNA)
Linux Linux9a65860959db594dfc1820c7fdc09285fb7556bfVendor (CNA)
Linux Linuxbf6e8af2c8be77489bedeae9f8a9654cb710e500Vendor (CNA)
Linux Linuxc6d3bcb0f934d4297ac5fa1c8656ae40694fb601Vendor (CNA)
debian:linux6.1.180-1 · 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).

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

Weakness class (CWE)

—

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/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. SSVC exploitation— → none
  2. Fix✗ → ✓

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

References

Show all references (5 more)

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

All records