In the Linux kernel, the following vulnerability has been resolved:
cachefiles: fix dentry leak in cachefiles_open_file()
A dentry leak may be caused when a lookup cookie and a cull are concurrent:
P1 | P2
-----------------------------------------------------------
cachefiles_lookup_cookie
cachefiles_look_up_object
lookup_one_positive_unlocked
// get dentry
cachefiles_cull
inode->i_flags |= S_KERNEL_FILE;
cachefiles_open_file
cachefiles_mark_inode_in_use
__cachefiles_mark_inode_in_use
can_use = false
if (!(inode->i_flags & S_KERNEL_FILE))
can_use = true
return false
return false
// Returns an error but doesn't put dentry
After that the following WARNING will be triggered when the backend folder
is umounted:
==================================================================
BUG: Dentry 000000008ad87947{i=7a,n=Dx_1_1.img} still in use (1) [unmount of ext4 sda]
WARNING: CPU: 4 PID: 359261 at fs/dcache.c:1767 umount_check+0x5d/0x70
CPU: 4 PID: 359261 Comm: umount Not tainted 6.6.0-dirty #25
RIP: 0010:umount_check+0x5d/0x70
Call Trace:
d_walk+0xda/0x2b0
do_one_tree+0x20/0x40
shrink_dcache_for_umount+0x2c/0x90
generic_shutdown_super+0x20/0x160
kill_block_super+0x1a/0x40
ext4_kill_sb+0x22/0x40
deactivate_locked_super+0x35/0x80
cleanup_mnt+0x104/0x160
==================================================================
Whether cachefiles_open_file() returns true or false, the reference count
obtained by lookup_positive_unlocked() in cachefiles_look_up_object()
should be released.
Therefore release that reference count in cachefiles_look_up_object() to
fix the above issue and simplify the code.
What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)
The EG score (5.5): severity, escalated by confirmed exploitation. This CVE's 5.5 is its impact severity (EG Severity), not escalated.
- EG Severity
- 5.5 MEDIUMCVSS-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 2026-10-25). 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 every mission impact level.CISA BOD 26-04: 60 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 every mission impact level.
A fix is available. Apply it within your standard update timelines.
Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (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)60 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 partial (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