CyberSecBulletin
CVE-2026-72019NVD status: Received

Linux: Out-of-bounds Read

Published Updated By the CyberSecBulletin desk

CVE-2026-72019 is a high-severity out-of-bounds read vulnerability in Linux, with a CVSS 3.1 base score of 7.3 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. The record lists versions b6cec6187b8632423cd99a94fd5e5ba165fa2a33, 3adea1b1c04b57e08a5c12a1f42483760581ce61, dc9ffa1905e72f026d080880a2e4cfc42aa91000 as the first without the flaw, so updating Linux to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.17% chance of exploitation within 30 days, which is low compared with other CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update Linux to b6cec6187b8632423cd99a94fd5e5ba165fa2a33 or 3adea1b1c04b57e08a5c12a1f42483760581ce61 or dc9ffa1905e72f026d080880a2e4cfc42aa91000 or f21fa533a3ed15ada74106aac4b9ddd078fc6b7a, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinuxc09440f7dcb304002dfced8c0fea289eb25f2da0 up to, but not including, b6cec6187b8632423cd99a94fd5e5ba165fa2a33; c09440f7dcb304002dfced8c0fea289eb25f2da0 up to, but not including, 3adea1b1c04b57e08a5c12a1f42483760581ce61; c09440f7dcb304002dfced8c0fea289eb25f2da0 up to, but not including, dc9ffa1905e72f026d080880a2e4cfc42aa91000; c09440f7dcb304002dfced8c0fea289eb25f2da0 up to, but not including, f21fa533a3ed15ada74106aac4b9ddd078fc6b7a; c09440f7dcb304002dfced8c0fea289eb25f2da0 up to, but not including, e17a42199824973cd8212e95b21ffadf4114a21b; c09440f7dcb304002dfced8c0fea289eb25f2da0 up to, but not including, 2cf10d042562283ff4ae97c02d0993d4f1b5ea29; c09440f7dcb304002dfced8c0fea289eb25f2da0 up to, but not including, c39087ad0b97fc11a3b058dfc8db9fd370762cb9; c09440f7dcb304002dfced8c0fea289eb25f2da0 up to, but not including, f5089008f90c0a7c5520dff3934e0af00adf322d; and 1 more rangesb6cec6187b8632423cd99a94fd5e5ba165fa2a33, 3adea1b1c04b57e08a5c12a1f42483760581ce61, dc9ffa1905e72f026d080880a2e4cfc42aa91000, f21fa533a3ed15ada74106aac4b9ddd078fc6b7a, e17a42199824973cd8212e95b21ffadf4114a21b, 2cf10d042562283ff4ae97c02d0993d4f1b5ea29

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
LocalThe attacker needs local access or must trick a user into running something.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
LowA basic user account is enough.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
HighAll data handled by the component can be read.
Integrity
LowLimited modification of data is possible.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:H. Scored by CNA.

Official description

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.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Out-of-bounds Read

The product reads data past the end, or before the beginning, of the intended buffer.

How developers prevent this class of flaw

  • Use a language that provides appropriate memory abstractions.

More Out-of-bounds Read vulnerabilities (CWE-125)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
  3. Record last changed materially (score, affected products, status or references).

References

Recent Out-of-bounds Read vulnerabilities

Spotted an error? Tell us.