In the Linux kernel, the following vulnerability has been resolved:
bpf, test_run: Fix use-after-free issue in eth_skb_pkt_type()
KMSAN reported a use-after-free issue in eth_skb_pkt_type()[1]. The
cause of the issue was that eth_skb_pkt_type() accessed skb's data
that didn't contain an Ethernet header. This occurs when
bpf_prog_test_run_xdp() passes an invalid value as the user_data
argument to bpf_test_init().
Fix this by returning an error when user_data is less than ETH_HLEN in
bpf_test_init(). Additionally, remove the check for "if (user_size >
size)" as it is unnecessary.
[1]
BUG: KMSAN: use-after-free in eth_skb_pkt_type include/linux/etherdevice.h:627 [inline]
BUG: KMSAN: use-after-free in eth_type_trans+0x4ee/0x980 net/ethernet/eth.c:165
eth_skb_pkt_type include/linux/etherdevice.h:627 [inline]
eth_type_trans+0x4ee/0x980 net/ethernet/eth.c:165
__xdp_build_skb_from_frame+0x5a8/0xa50 net/core/xdp.c:635
xdp_recv_frames net/bpf/test_run.c:272 [inline]
xdp_test_run_batch net/bpf/test_run.c:361 [inline]
bpf_test_run_xdp_live+0x2954/0x3330 net/bpf/test_run.c:390
bpf_prog_test_run_xdp+0x148e/0x1b10 net/bpf/test_run.c:1318
bpf_prog_test_run+0x5b7/0xa30 kernel/bpf/syscall.c:4371
__sys_bpf+0x6a6/0xe20 kernel/bpf/syscall.c:5777
__do_sys_bpf kernel/bpf/syscall.c:5866 [inline]
__se_sys_bpf kernel/bpf/syscall.c:5864 [inline]
__x64_sys_bpf+0xa4/0xf0 kernel/bpf/syscall.c:5864
x64_sys_call+0x2ea0/0x3d90 arch/x86/include/generated/asm/syscalls_64.h:322
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xd9/0x1d0 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
Uninit was created at:
free_pages_prepare mm/page_alloc.c:1056 [inline]
free_unref_page+0x156/0x1320 mm/page_alloc.c:2657
__free_pages+0xa3/0x1b0 mm/page_alloc.c:4838
bpf_ringbuf_free kernel/bpf/ringbuf.c:226 [inline]
ringbuf_map_free+0xff/0x1e0 kernel/bpf/ringbuf.c:235
bpf_map_free kernel/bpf/syscall.c:838 [inline]
bpf_map_free_deferred+0x17c/0x310 kernel/bpf/syscall.c:862
process_one_work kernel/workqueue.c:3229 [inline]
process_scheduled_works+0xa2b/0x1b60 kernel/workqueue.c:3310
worker_thread+0xedf/0x1550 kernel/workqueue.c:3391
kthread+0x535/0x6b0 kernel/kthread.c:389
ret_from_fork+0x6e/0x90 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
CPU: 1 UID: 0 PID: 17276 Comm: syz.1.16450 Not tainted 6.12.0-05490-g9bb88c659673 #8
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-3.fc41 04/01/2014
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 2026-10-28). 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