In the Linux kernel, the following vulnerability has been resolved:
nvme-tcp: remove tag set when second admin queue config fails
Commit 104d0e2f6222 ("nvme-fabrics: reset admin connection for secure
concatenation") modified nvme_tcp_setup_ctrl() to call
nvme_tcp_configure_admin_queue() twice. The first call prepares for
DH-CHAP negotitation, and the second call is required for secure
concatenation. However, this change triggered BUG KASAN slab-use-after-
free in blk_mq_queue_tag_busy_iter(). This BUG can be recreated by
repeating the blktests test case nvme/063 a few times [1].
When the BUG happens, nvme_tcp_create_ctrl() fails in the call chain
below:
nvme_tcp_create_ctrl()
nvme_tcp_alloc_ctrl() new=true ... Alloc nvme_tcp_ctrl and admin_tag_set
nvme_tcp_setup_ctrl() new=true
nvme_tcp_configure_admin_queue() new=true ... Succeed
nvme_alloc_admin_tag_set() ... Alloc the tag set for admin_tag_set
nvme_stop_keep_alive()
nvme_tcp_teardown_admin_queue() remove=false
nvme_tcp_configure_admin_queue() new=false
nvme_tcp_alloc_admin_queue() ... Fail, but do not call nvme_remove_admin_tag_set()
nvme_uninit_ctrl()
nvme_put_ctrl() ... Free up the nvme_tcp_ctrl and admin_tag_set
The first call of nvme_tcp_configure_admin_queue() succeeds with
new=true argument. The second call fails with new=false argument. This
second call does not call nvme_remove_admin_tag_set() on failure, due to
the new=false argument. Then the admin tag set is not removed. However,
nvme_tcp_create_ctrl() assumes that nvme_tcp_setup_ctrl() would call
nvme_remove_admin_tag_set(). Then it frees up struct nvme_tcp_ctrl which
has admin_tag_set field. Later on, the timeout handler accesses the
admin_tag_set field and causes the BUG KASAN slab-use-after-free.
To not leave the admin tag set, call nvme_remove_admin_tag_set() when
the second nvme_tcp_configure_admin_queue() call fails. Do not return
from nvme_tcp_setup_ctrl() on failure. Instead, jump to "destroy_admin"
go-to label to call nvme_tcp_teardown_admin_queue() which calls
nvme_remove_admin_tag_set().
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
- 0.4% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-30). 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; Attend at high (mission-essential systems).CISA BOD 26-04: 3 days if the affected system is publicly exposed; 60 days 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; Attend at high (mission-essential systems).
A fixed version is listed under Patch Availability. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
Exploitation none (CISA Vulnrichment) · Automatable yes (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)3 days if the affected system is publicly exposed; 60 days if it is not.
The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable yes (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