In the Linux kernel, the following vulnerability has been resolved:
macsec: Fix use-after-free while sending the offloading packet
KASAN reports the following UAF. The metadata_dst, which is used to
store the SCI value for macsec offload, is already freed by
metadata_dst_free() in macsec_free_netdev(), while driver still use it
for sending the packet.
To fix this issue, dst_release() is used instead to release
metadata_dst. So it is not freed instantly in macsec_free_netdev() if
still referenced by skb.
BUG: KASAN: slab-use-after-free in mlx5e_xmit+0x1e8f/0x4190 [mlx5_core]
Read of size 2 at addr ffff88813e42e038 by task kworker/7:2/714
[...]
Workqueue: mld mld_ifc_work
Call Trace:
dump_stack_lvl+0x51/0x60
print_report+0xc1/0x600
kasan_report+0xab/0xe0
mlx5e_xmit+0x1e8f/0x4190 [mlx5_core]
dev_hard_start_xmit+0x120/0x530
sch_direct_xmit+0x149/0x11e0
__qdisc_run+0x3ad/0x1730
__dev_queue_xmit+0x1196/0x2ed0
vlan_dev_hard_start_xmit+0x32e/0x510 [8021q]
dev_hard_start_xmit+0x120/0x530
__dev_queue_xmit+0x14a7/0x2ed0
macsec_start_xmit+0x13e9/0x2340
dev_hard_start_xmit+0x120/0x530
__dev_queue_xmit+0x14a7/0x2ed0
ip6_finish_output2+0x923/0x1a70
ip6_finish_output+0x2d7/0x970
ip6_output+0x1ce/0x3a0
NF_HOOK.constprop.0+0x15f/0x190
mld_sendpack+0x59a/0xbd0
mld_ifc_work+0x48a/0xa80
process_one_work+0x5aa/0xe50
worker_thread+0x79c/0x1290
kthread+0x28f/0x350
ret_from_fork+0x2d/0x70
ret_from_fork_asm+0x11/0x20
Allocated by task 3922:
kasan_save_stack+0x20/0x40
kasan_save_track+0x10/0x30
__kasan_kmalloc+0x77/0x90
__kmalloc_noprof+0x188/0x400
metadata_dst_alloc+0x1f/0x4e0
macsec_newlink+0x914/0x1410
__rtnl_newlink+0xe08/0x15b0
rtnl_newlink+0x5f/0x90
rtnetlink_rcv_msg+0x667/0xa80
netlink_rcv_skb+0x12c/0x360
netlink_unicast+0x551/0x770
netlink_sendmsg+0x72d/0xbd0
__sock_sendmsg+0xc5/0x190
____sys_sendmsg+0x52e/0x6a0
___sys_sendmsg+0xeb/0x170
__sys_sendmsg+0xb5/0x140
do_syscall_64+0x4c/0x100
entry_SYSCALL_64_after_hwframe+0x4b/0x53
Freed by task 4011:
kasan_save_stack+0x20/0x40
kasan_save_track+0x10/0x30
kasan_save_free_info+0x37/0x50
poison_slab_object+0x10c/0x190
__kasan_slab_free+0x11/0x30
kfree+0xe0/0x290
macsec_free_netdev+0x3f/0x140
netdev_run_todo+0x450/0xc70
rtnetlink_rcv_msg+0x66f/0xa80
netlink_rcv_skb+0x12c/0x360
netlink_unicast+0x551/0x770
netlink_sendmsg+0x72d/0xbd0
__sock_sendmsg+0xc5/0x190
____sys_sendmsg+0x52e/0x6a0
___sys_sendmsg+0xeb/0x170
__sys_sendmsg+0xb5/0x140
do_syscall_64+0x4c/0x100
entry_SYSCALL_64_after_hwframe+0x4b/0x53
What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)
The EG score (7.8): severity, escalated by confirmed exploitation. This CVE's 7.8 is its impact severity (EG Severity), not escalated.
- EG Severity
- 7.8 HIGHCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
- EG Likelihood
- 0.2% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-27). FIRST's exploitation probability, not an EchelonGraph model.
- Confirmed exploitation
- None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
- EG Priority
- SSVC Track at medium mission impactTrack at low or medium mission impact; Track* at high (mission-essential systems).CISA BOD 26-04: 14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.Each input and its source, and whom BOD 26-04 binds: the SSVC and BOD 26-04 blocks below.
SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Track* at high (mission-essential systems).
A fix is available. Apply it within your standard update timelines.
Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table
BOD 26-04 (CISA's remediation timeline, Table 1)14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.
The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it