In the Linux kernel, the following vulnerability has been resolved:
coresight: tmc-etr: Fix race condition between sysfs and perf mode
When trying to run perf and sysfs mode simultaneously, the WARN_ON()
in tmc_etr_enable_hw() is triggered sometimes:
WARNING: CPU: 42 PID: 3911571 at drivers/hwtracing/coresight/coresight-tmc-etr.c:1060 tmc_etr_enable_hw+0xc0/0xd8 [coresight_tmc]
[..snip..]
Call trace:
tmc_etr_enable_hw+0xc0/0xd8 [coresight_tmc] (P)
tmc_enable_etr_sink+0x11c/0x250 [coresight_tmc] (L)
tmc_enable_etr_sink+0x11c/0x250 [coresight_tmc]
coresight_enable_path+0x1c8/0x218 [coresight]
coresight_enable_sysfs+0xa4/0x228 [coresight]
enable_source_store+0x58/0xa8 [coresight]
dev_attr_store+0x20/0x40
sysfs_kf_write+0x4c/0x68
kernfs_fop_write_iter+0x120/0x1b8
vfs_write+0x2c8/0x388
ksys_write+0x74/0x108
__arm64_sys_write+0x24/0x38
el0_svc_common.constprop.0+0x64/0x148
do_el0_svc+0x24/0x38
el0_svc+0x3c/0x130
el0t_64_sync_handler+0xc8/0xd0
el0t_64_sync+0x1ac/0x1b0
---[ end trace 0000000000000000 ]---
Since the enablement of sysfs mode is separeted into two critical regions,
one for sysfs buffer allocation and another for hardware enablement, it's
possible to race with the perf mode. Fix this by double check whether
the perf mode's been used before enabling the hardware in sysfs mode.
mode:
[sysfs mode] [perf mode]
tmc_etr_get_sysfs_buffer()
spin_lock(&drvdata->spinlock)
[sysfs buffer allocation]
spin_unlock(&drvdata->spinlock)
spin_lock(&drvdata->spinlock)
tmc_etr_enable_hw()
drvdata->etr_buf = etr_perf->etr_buf
spin_unlock(&drvdata->spinlock)
spin_lock(&drvdata->spinlock)
tmc_etr_enable_hw()
WARN_ON(drvdata->etr_buf) // WARN sicne etr_buf initialized at
the perf side
spin_unlock(&drvdata->spinlock)
With this fix, we retain the check for CS_MODE_PERF in get_etr_sysfs_buf.
This ensures we verify whether the perf mode's already running before we
actually allocate the buffer. Then we can save the time of
allocating/freeing the sysfs buffer if race with the perf mode.
What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)
The EG score (4.7): severity, escalated by confirmed exploitation. This CVE's 4.7 is its impact severity (EG Severity), not escalated.
- EG Severity
- 4.7 MEDIUMCVSS-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 2026-10-24). 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 (no CISA value, KEV listing or exploit code on record) · Automatable no (CISA's BOD 26-04 default) · Technical impact total (CISA's BOD 26-04 default). EchelonGraph holds no SSVC assessment of this CVE from CISA: none of these inputs is from 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's BOD 26-04 default) · Technical impact total (CISA's BOD 26-04 default). Where an input reads “CISA's BOD 26-04 default”, no one has published it for this CVE, and CISA's implementation guidance says: “If “Automatable” and “Technical Impact” information items about a CVE ID are not available and the CVE ID is not in the KEV Catalog, CISA will treat its values as “no” and “total,” respectively, until CISA or a third party provides metadata about the CVE ID. CISA will always provide the Vulnrichment data for a CVE ID listed in the KEV Catalog.” 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