In the Linux kernel, the following vulnerability has been resolved:
net/smc: fix LGR and link use-after-free issue
We encountered a LGR/link use-after-free issue, which manifested as
the LGR/link refcnt reaching 0 early and entering the clear process,
making resource access unsafe.
refcount_t: addition on 0; use-after-free.
WARNING: CPU: 14 PID: 107447 at lib/refcount.c:25 refcount_warn_saturate+0x9c/0x140
Workqueue: events smc_lgr_terminate_work [smc]
Call trace:
refcount_warn_saturate+0x9c/0x140
__smc_lgr_terminate.part.45+0x2a8/0x370 [smc]
smc_lgr_terminate_work+0x28/0x30 [smc]
process_one_work+0x1b8/0x420
worker_thread+0x158/0x510
kthread+0x114/0x118
or
refcount_t: underflow; use-after-free.
WARNING: CPU: 6 PID: 93140 at lib/refcount.c:28 refcount_warn_saturate+0xf0/0x140
Workqueue: smc_hs_wq smc_listen_work [smc]
Call trace:
refcount_warn_saturate+0xf0/0x140
smcr_link_put+0x1cc/0x1d8 [smc]
smc_conn_free+0x110/0x1b0 [smc]
smc_conn_abort+0x50/0x60 [smc]
smc_listen_find_device+0x75c/0x790 [smc]
smc_listen_work+0x368/0x8a0 [smc]
process_one_work+0x1b8/0x420
worker_thread+0x158/0x510
kthread+0x114/0x118
It is caused by repeated release of LGR/link refcnt. One suspect is that
smc_conn_free() is called repeatedly because some smc_conn_free() from
server listening path are not protected by sock lock.
e.g.
Calls under socklock | smc_listen_work
-------------------------------------------------------
lock_sock(sk) | smc_conn_abort
smc_conn_free | \- smc_conn_free
\- smcr_link_put | \- smcr_link_put (duplicated)
release_sock(sk)
So here add sock lock protection in smc_listen_work() path, making it
exclusive with other connection operations.
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
- 0.6% 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