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CVE Record

CVE-2021-47212: net/mlx5: Update error handler for UCTX and UMEM

In the Linux kernel, the following vulnerability has been resolved: net/mlx5: Update error handler for UCTX and UMEM In the fast unload flow, the device state is set to internal error, which indicates that the driver started the destroy process. In this case, when a destroy command is being executed, it should return MLX5_CMD_STAT_OK. Fix MLX5_CMD_OP_DESTROY_UCTX and MLX5_CMD_OP_DESTROY_UMEM to return OK instead of EIO. This fixes a call trace in the umem release process - [ 2633.536695] Call Trace: [ 2633.537518] ib_uverbs_remove_one+0xc3/0x140 [ib_uverbs] [ 2633.538596] remove_client_context+0x8b/0xd0 [ib_core] [ 2633.539641] disable_device+0x8c/0x130 [ib_core] [ 2633.540615] __ib_unregister_device+0x35/0xa0 [ib_core] [ 2633.541640] ib_unregister_device+0x21/0x30 [ib_core] [ 2633.542663] __mlx5_ib_remove+0x38/0x90 [mlx5_ib] [ 2633.543640] auxiliary_bus_remove+0x1e/0x30 [auxiliary] [ 2633.544661] device_release_driver_internal+0x103/0x1f0 [ 2633.545679] bus_remove_device+0xf7/0x170 [ 2633.546640] device_del+0x181/0x410 [ 2633.547606] mlx5_rescan_drivers_locked.part.10+0x63/0x160 [mlx5_core] [ 2633.548777] mlx5_unregister_device+0x27/0x40 [mlx5_core] [ 2633.549841] mlx5_uninit_one+0x21/0xc0 [mlx5_core] [ 2633.550864] remove_one+0x69/0xe0 [mlx5_core] [ 2633.551819] pci_device_remove+0x3b/0xc0 [ 2633.552731] device_release_driver_internal+0x103/0x1f0 [ 2633.553746] unbind_store+0xf6/0x130 [ 2633.554657] kernfs_fop_write+0x116/0x190 [ 2633.555567] vfs_write+0xa5/0x1a0 [ 2633.556407] ksys_write+0x4f/0xb0 [ 2633.557233] do_syscall_64+0x5b/0x1a0 [ 2633.558071] entry_SYSCALL_64_after_hwframe+0x65/0xca [ 2633.559018] RIP: 0033:0x7f9977132648 [ 2633.559821] Code: 89 02 48 c7 c0 ff ff ff ff eb b3 0f 1f 80 00 00 00 00 f3 0f 1e fa 48 8d 05 55 6f 2d 00 8b 00 85 c0 75 17 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 58 c3 0f 1f 80 00 00 00 00 41 54 49 89 d4 55 [ 2633.562332] RSP: 002b:00007fffb1a83888 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 [ 2633.563472] RAX: ffffffffffffffda RBX: 000000000000000c RCX: 00007f9977132648 [ 2633.564541] RDX: 000000000000000c RSI: 000055b90546e230 RDI: 0000000000000001 [ 2633.565596] RBP: 000055b90546e230 R08: 00007f9977406860 R09: 00007f9977a54740 [ 2633.566653] R10: 0000000000000000 R11: 0000000000000246 R12: 00007f99774056e0 [ 2633.567692] R13: 000000000000000c R14: 00007f9977400880 R15: 000000000000000c [ 2633.568725] ---[ end trace 10b4fe52945e544d ]---

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysisunknown

Security readout for executives and security teams

Plain-English summary

This Linux kernel issue affects mlx5 driver cleanup during fast device unload. The driver returned an I/O error for UCTX and UMEM destroy operations after entering internal-error teardown, causing a kernel call trace during UMEM release. The available sources indicate a reliability and operational stability issue, not confirmed active exploitation.

Executive priority

Treat this as a targeted kernel driver reliability fix unless local exposure to mlx5/RDMA infrastructure is confirmed. Prioritize affected high-availability, virtualization, storage, or networking hosts where driver unload failures and kernel traces could disrupt operations.

Technical view

CVE-2021-47212 resolves mlx5 error handling for MLX5_CMD_OP_DESTROY_UCTX and MLX5_CMD_OP_DESTROY_UMEM. During fast unload, the device enters an internal error state; destroy commands should return MLX5_CMD_STAT_OK instead of EIO. The reported impact is a call trace through ib_uverbs, ib_core, mlx5_ib, and mlx5_core during device removal.

Likely exposure

Exposure is most plausible on Linux systems using the mlx5 stack with InfiniBand/RDMA-related components. The source bundle lists Linux kernel versions including 5.2, 5.15.5, and 5.16 as affected, but gives limited product and distribution mapping.

Exploitation context

The source bundle does not cite CISA KEV listing, active exploitation, a public exploit, remote reachability, or required attacker privileges. The evidence is limited to kernel commit references and a call trace triggered during fast unload or device removal behavior.

Researcher notes

The record lacks CVSS, CWE, exploit details, and distribution-specific package boundaries. Analysis should stay tied to mlx5 fast unload behavior and the two referenced stable commits. Avoid assuming broader kernel compromise without additional vendor evidence.

Mitigation direction

  • Update to a Linux kernel containing the referenced stable fixes.
  • Check distribution vendor advisories for packaged kernel backports.
  • Prioritize systems using mlx5, mlx5_ib, ib_uverbs, or RDMA functions.
  • Schedule updates around maintenance windows for affected driver hosts.
  • Monitor vendor guidance if fixed package mapping is unclear.

Validation and detection

  • Inventory Linux kernel versions against vendor CVE or changelog data.
  • Confirm whether mlx5-related drivers or RDMA functions are in use.
  • Review kernel logs for matching unload or UMEM release call traces.
  • Validate device unload and removal workflows after patching.
  • Track remediation status separately for source-built and vendor kernels.
Prepared
Confidence
medium
Sources
4

Public sources used

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
2ADP providers
3Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: noneAutomatable: noTechnical Impact: partial

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

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ADP provider summaries

CISA-ADPCISA ADP Vulnrichment
other:ssvc
CVECVE Program Container

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinux6a6fabbfa3e8c656ff906ae999fb6856410fa4cd, 6a6fabbfa3e8c656ff906ae999fb6856410fa4cdunaffected
LinuxLinux5.2, 0, 5.15.5, 5.16affected
Weakness

CWE details

No CWE listed

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