In the Linux kernel, the following vulnerability has been resolved:
net/smc: fix double-free of smc_spd_priv when tee() duplicates splice pipe buffer
smc_rx_splice() allocates one smc_spd_priv per pipe_buffer and stores
the pointer in pipe_buffer.private. The pipe_buf_operations for these
buffers used .get = generic_pipe_buf_get, which only increments the page
reference count when tee(2) duplicates a pipe buffer. The smc_spd_priv
pointer itself was not handled, so after tee() both the original and the
cloned pipe_buffer share the same smc_spd_priv *.
When both pipes are subsequently released, smc_rx_pipe_buf_release() is
called twice against the same object:
1st call: kfree(priv) sock_put(sk) smc_rx_update_cons() [correct]
2nd call: kfree(priv) sock_put(sk) smc_rx_update_cons() [UAF]
KASAN reports a slab-use-after-free in smc_rx_pipe_buf_release(), which
then escalates to a NULL-pointer dereference and kernel panic via
smc_rx_update_consumer() when it chases the freed priv->smc pointer:
BUG: KASAN: slab-use-after-free in smc_rx_pipe_buf_release+0x78/0x2a0
Read of size 8 at addr ffff888004a45740 by task smc_splice_tee_/74
Call Trace:
dump_stack_lvl+0x53/0x70
print_report+0xce/0x650
kasan_report+0xc6/0x100
smc_rx_pipe_buf_release+0x78/0x2a0
free_pipe_info+0xd4/0x130
pipe_release+0x142/0x160
__fput+0x1c6/0x490
__x64_sys_close+0x4f/0x90
do_syscall_64+0xa6/0x1a0
entry_SYSCALL_64_after_hwframe+0x77/0x7f
BUG: kernel NULL pointer dereference, address: 0000000000000020
RIP: 0010:smc_rx_update_consumer+0x8d/0x350
Call Trace:
smc_rx_pipe_buf_release+0x121/0x2a0
free_pipe_info+0xd4/0x130
pipe_release+0x142/0x160
__fput+0x1c6/0x490
__x64_sys_close+0x4f/0x90
do_syscall_64+0xa6/0x1a0
entry_SYSCALL_64_after_hwframe+0x77/0x7f
Kernel panic - not syncing: Fatal exception
Beyond the memory-safety problem, duplicating an SMC splice buffer is
semantically questionable: smc_rx_update_cons() would advance the
consumer cursor twice for the same data, corrupting receive-window
accounting. A refcount on smc_spd_priv could fix the double-free, but
the cursor-accounting issue would still need to be addressed separately.
The .get callback is invoked by both tee(2) and splice_pipe_to_pipe()
for partial transfers; both will now return -EFAULT. Users who need
to duplicate SMC socket data must use a copy-based read path.
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
- 0.1% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-11-11). 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