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CVE Record

CVE-2022-50214: coresight: Clear the connection field properly

In the Linux kernel, the following vulnerability has been resolved: coresight: Clear the connection field properly coresight devices track their connections (output connections) and hold a reference to the fwnode. When a device goes away, we walk through the devices on the coresight bus and make sure that the references are dropped. This happens both ways: a) For all output connections from the device, drop the reference to the target device via coresight_release_platform_data() b) Iterate over all the devices on the coresight bus and drop the reference to fwnode if *this* device is the target of the output connection, via coresight_remove_conns()->coresight_remove_match(). However, the coresight_remove_match() doesn't clear the fwnode field, after dropping the reference, this causes use-after-free and additional refcount drops on the fwnode. e.g., if we have two devices, A and B, with a connection, A -> B. If we remove B first, B would clear the reference on B, from A via coresight_remove_match(). But when A is removed, it still has a connection with fwnode still pointing to B. Thus it tries to drops the reference in coresight_release_platform_data(), raising the bells like : [ 91.990153] ------------[ cut here ]------------ [ 91.990163] refcount_t: addition on 0; use-after-free. [ 91.990212] WARNING: CPU: 0 PID: 461 at lib/refcount.c:25 refcount_warn_saturate+0xa0/0x144 [ 91.990260] Modules linked in: coresight_funnel coresight_replicator coresight_etm4x(-) crct10dif_ce coresight ip_tables x_tables ipv6 [last unloaded: coresight_cpu_debug] [ 91.990398] CPU: 0 PID: 461 Comm: rmmod Tainted: G W T 5.19.0-rc2+ #53 [ 91.990418] Hardware name: ARM LTD ARM Juno Development Platform/ARM Juno Development Platform, BIOS EDK II Feb 1 2019 [ 91.990434] pstate: 600000c5 (nZCv daIF -PAN -UAO -TCO -DIT -SSBS BTYPE=--) [ 91.990454] pc : refcount_warn_saturate+0xa0/0x144 [ 91.990476] lr : refcount_warn_saturate+0xa0/0x144 [ 91.990496] sp : ffff80000c843640 [ 91.990509] x29: ffff80000c843640 x28: ffff800009957c28 x27: ffff80000c8439a8 [ 91.990560] x26: ffff00097eff1990 x25: ffff8000092b6ad8 x24: ffff00097eff19a8 [ 91.990610] x23: ffff80000c8439a8 x22: 0000000000000000 x21: ffff80000c8439c2 [ 91.990659] x20: 0000000000000000 x19: ffff00097eff1a10 x18: ffff80000ab99c40 [ 91.990708] x17: 0000000000000000 x16: 0000000000000000 x15: ffff80000abf6fa0 [ 91.990756] x14: 000000000000001d x13: 0a2e656572662d72 x12: 657466612d657375 [ 91.990805] x11: 203b30206e6f206e x10: 6f69746964646120 x9 : ffff8000081aba28 [ 91.990854] x8 : 206e6f206e6f6974 x7 : 69646461203a745f x6 : 746e756f63666572 [ 91.990903] x5 : ffff00097648ec58 x4 : 0000000000000000 x3 : 0000000000000027 [ 91.990952] x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffff00080260ba00 [ 91.991000] Call trace: [ 91.991012] refcount_warn_saturate+0xa0/0x144 [ 91.991034] kobject_get+0xac/0xb0 [ 91.991055] of_node_get+0x2c/0x40 [ 91.991076] of_fwnode_get+0x40/0x60 [ 91.991094] fwnode_handle_get+0x3c/0x60 [ 91.991116] fwnode_get_nth_parent+0xf4/0x110 [ 91.991137] fwnode_full_name_string+0x48/0xc0 [ 91.991158] device_node_string+0x41c/0x530 [ 91.991178] pointer+0x320/0x3ec [ 91.991198] vsnprintf+0x23c/0x750 [ 91.991217] vprintk_store+0x104/0x4b0 [ 91.991238] vprintk_emit+0x8c/0x360 [ 91.991257] vprintk_default+0x44/0x50 [ 91.991276] vprintk+0xcc/0xf0 [ 91.991295] _printk+0x68/0x90 [ 91.991315] of_node_release+0x13c/0x14c [ 91.991334] kobject_put+0x98/0x114 [ 91.991354] of_node_put+0x24/0x34 [ 91.991372] of_fwnode_put+0x40/0x5c [ 91.991390] fwnode_handle_put+0x38/0x50 [ 91.991411] coresight_release_platform_data+0x74/0xb0 [coresight] [ 91.991472] coresight_unregister+0x64/0xcc [coresight] [ 91.991525] etm4_remove_dev+0x64/0x78 [coresight_etm4x] [ 91.991563] etm4_remove_amba+0x1c/0x2c [coresight_etm4x] [ 91.991598] amba_remove+0x3c/0x19c ---truncated---

UnknownCVSS not scoredNot KEV-listedUpdated
Glexia's TakeAutomated analysisunknown

Security readout for executives and security teams

Plain-English summary

CVE-2022-50214 is a Linux kernel CoreSight cleanup bug. When connected CoreSight devices are removed in certain orders, stale firmware-node references can remain and trigger use-after-free/refcount errors. The bundle does not show remote exposure, active exploitation, or a scored severity.

Executive priority

Treat this as targeted kernel maintenance, not an internet-wide emergency. Prioritize embedded, ARM, lab, or production systems that use CoreSight. The absence of CVSS and exploitation evidence lowers urgency, but kernel memory-safety bugs still warrant normal patch governance.

Technical view

The CoreSight bus drops fwnode references for output connections during device removal, but coresight_remove_match() did not clear the fwnode field after put. Later removal of a connected device can reuse the stale pointer and perform additional refcount operations, producing use-after-free warnings in the kernel.

Likely exposure

Exposure is most likely on Linux systems using ARM CoreSight tracing/debug components or related loadable modules. General Linux servers without CoreSight hardware or enabled drivers may not be affected in practice. Confirm exposure by kernel version, enabled CoreSight configuration, loaded modules, and vendor kernel backports.

Exploitation context

The provided sources show a kernel warning during CoreSight module/device removal on an ARM Juno platform. KEV is false, and the bundle provides no evidence of active exploitation, public weaponization, or remote attackability.

Researcher notes

The key condition is stale fwnode retention after coresight_remove_match() drops a reference. The source example involves A -> B connections and removal of B before A. Assess whether downstream kernels carry the fix commits and whether local configurations exercise CoreSight unregister paths.

Mitigation direction

  • Check distribution or device-vendor advisories for a kernel containing the listed stable fixes.
  • Prioritize patching systems that enable ARM CoreSight drivers or load CoreSight modules.
  • If patching is delayed, reduce unnecessary CoreSight module use where operationally feasible.
  • Track vendor backports rather than relying only on upstream version numbers.

Validation and detection

  • Inventory kernels and identify systems with CoreSight support enabled or modules loaded.
  • Compare installed kernel source or changelog against the referenced stable commits.
  • Review kernel logs for CoreSight removal warnings or refcount/use-after-free messages.
  • Confirm vendor packages include the fix before closing remediation.
Prepared
Confidence
medium
Sources
8

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors
3Timeline events
0ADP providers
7Source links

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. CVE publishedCVE Program

    The CVE record was published.

  3. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinux37ea1ffddffa63c920ce826786fe610c78f57842, 37ea1ffddffa63c920ce826786fe610c78f57842, 37ea1ffddffa63c920ce826786fe610c78f57842, 37ea1ffddffa63c920ce826786fe610c78f57842, 37ea1ffddffa63c920ce826786fe610c78f57842, 37ea1ffddffa63c920ce826786fe610c78f57842unaffected
LinuxLinux5.3, 0, 5.4.211, 5.10.137, 5.15.61, 5.18.18, 5.19.2, 6.0affected
Weakness

CWE details

No CWE listed

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