Skip to content
Noroxi
NVD / CVE Program· CNA Linux

CVE-2026-72019: macsec: don't read an unset MAC header in macsec_encrypt()

Noroxi assessment

Priority: Monitor (action score 29/100)

  • 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).
  • 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 2cf10d042562283ff4ae97c02d0993d4f1b5ea29, 3adea1b1c04b57e08a5c12a1f42483760581ce61, b6cec6187b8632423cd99a94fd5e5ba165fa2a33.

Low priority for now. Upgrade to Linux Linux 2cf10d042562283ff4ae97c02d0993d4f1b5ea29, 3adea1b1c04b57e08a5c12a1f42483760581ce61, b6cec6187b8632423cd99a94fd5e5ba165fa2a33 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: macsec: don't read an unset MAC header in macsec_encrypt() macsec_encrypt() reads the Ethernet header via eth_hdr(skb) (skb->head + skb->mac_header) to memmove() the 12 source/destination MAC bytes forward and make room for the SecTAG. On the AF_PACKET SOCK_RAW + PACKET_QDISC_BYPASS transmit path the skb reaches the macsec ndo_start_xmit() with the MAC header unset, so eth_hdr(skb) resolves to skb->head + (u16)~0 and the read is out of bounds: a 12-byte heap over-read that is also emitted on the wire as the frame's outer source/destination MAC. KASAN reports a slab-out-of-bounds read in macsec_start_xmit() on 6.0; on current mainline a CONFIG_DEBUG_NET build flags it as an unset mac header in skb_mac_header(). On the TX path the L2 header is at skb->data, so use skb_eth_hdr(), added by commit 96cc4b69581d ("macvlan: do not assume mac_header is set in macvlan_broadcast()") for exactly this purpose.

HighCVSS 7.3 · v3.1—No exploit Fix available
Published
Aug 15, 2026
Updated
Oct 19, 2026
EPSS
0.1% · 6th percentile

Report tools

JSON

Action score

29

Monitor

Low priority for now.

CVSS
29 / 40 · 7.3 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · Linux
7.3
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-2026-72019

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.

—

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

    • 4.6affected
    • c09440f7dcb304002dfced8c0fea289eb25f2da0 and later · before b6cec6187b8632423cd99a94fd5e5ba165fa2a33affected · git
    • c09440f7dcb304002dfced8c0fea289eb25f2da0 and later · before 3adea1b1c04b57e08a5c12a1f42483760581ce61affected · git
    • c09440f7dcb304002dfced8c0fea289eb25f2da0 and later · before dc9ffa1905e72f026d080880a2e4cfc42aa91000affected · git
    • c09440f7dcb304002dfced8c0fea289eb25f2da0 and later · before f21fa533a3ed15ada74106aac4b9ddd078fc6b7aaffected · git
    • c09440f7dcb304002dfced8c0fea289eb25f2da0 and later · before e17a42199824973cd8212e95b21ffadf4114a21baffected · git
    • c09440f7dcb304002dfced8c0fea289eb25f2da0 and later · before 2cf10d042562283ff4ae97c02d0993d4f1b5ea29affected · git
    • c09440f7dcb304002dfced8c0fea289eb25f2da0 and later · before c39087ad0b97fc11a3b058dfc8db9fd370762cb9affected · git
    • c09440f7dcb304002dfced8c0fea289eb25f2da0 and later · before f5089008f90c0a7c5520dff3934e0af00adf322daffected · git
    • before 4.6not 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-2026-72014Aug 15, 2026 · drbd: reject data replies with an out-of-range payload size
    39Monitor
  • ← EarlierCVE-2026-72018Aug 15, 2026 · dibs: loopback: validate offset and size in move_data()
    31Monitor
  • Later →CVE-2026-72020Aug 15, 2026 · ipvs: reset full ip_vs_seq structs in ip_vs_conn_new
    39Monitor

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 Linux2cf10d042562283ff4ae97c02d0993d4f1b5ea29Vendor (CNA)
Linux Linux3adea1b1c04b57e08a5c12a1f42483760581ce61Vendor (CNA)
Linux Linuxb6cec6187b8632423cd99a94fd5e5ba165fa2a33Vendor (CNA)
Linux Linuxc39087ad0b97fc11a3b058dfc8db9fd370762cb9Vendor (CNA)
Linux Linuxdc9ffa1905e72f026d080880a2e4cfc42aa91000Vendor (CNA)
Linux Linuxe17a42199824973cd8212e95b21ffadf4114a21bVendor (CNA)
Linux Linuxf21fa533a3ed15ada74106aac4b9ddd078fc6b7aVendor (CNA)
Linux Linuxf5089008f90c0a7c5520dff3934e0af00adf322dVendor (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.

  • CVE-2026-720840 days apartscsi: target: Bound PR-OUT TransportID parsing to the received buffer
    39Monitor
  • CVE-2026-681605 days apartceph: fix pre-auth out-of-bounds read on snaptrace in ceph_handle_caps()
    39Monitor
  • CVE-2026-683885 days apartsmb/client: handle overlapping allocated ranges in fallocate
    39Monitor
  • CVE-2026-680827 days apartlibceph: fix two unsafe bare decodes in decode_lockers()
    39Monitor
  • CVE-2026-683435 days apartsmb: client: validate DFS referral PathConsumed
    36Monitor
  • CVE-2026-6455119 days apartsctp: validate STALE_COOKIE cause length before reading staleness
    36Monitor

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
low · 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
Low
Availability impact
High

Weakness class (CWE)

CWE-125 · Out-of-bounds Read

CVSS vector

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

ATT&CK techniques

—

Change log

  1. SSVC exploitation— → none
  2. Fix✗ → ✓

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

References

Show all references (7 more)

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

All records