LiveActive security incident?Get immediate response
CVE Record

CVE-2021-47292: io_uring: fix memleak in io_init_wq_offload()

In the Linux kernel, the following vulnerability has been resolved: io_uring: fix memleak in io_init_wq_offload() I got memory leak report when doing fuzz test: BUG: memory leak unreferenced object 0xffff888107310a80 (size 96): comm "syz-executor.6", pid 4610, jiffies 4295140240 (age 20.135s) hex dump (first 32 bytes): 01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00 00 00 00 ad 4e ad de ff ff ff ff 00 00 00 00 .....N.......... backtrace: [<000000001974933b>] kmalloc include/linux/slab.h:591 [inline] [<000000001974933b>] kzalloc include/linux/slab.h:721 [inline] [<000000001974933b>] io_init_wq_offload fs/io_uring.c:7920 [inline] [<000000001974933b>] io_uring_alloc_task_context+0x466/0x640 fs/io_uring.c:7955 [<0000000039d0800d>] __io_uring_add_tctx_node+0x256/0x360 fs/io_uring.c:9016 [<000000008482e78c>] io_uring_add_tctx_node fs/io_uring.c:9052 [inline] [<000000008482e78c>] __do_sys_io_uring_enter fs/io_uring.c:9354 [inline] [<000000008482e78c>] __se_sys_io_uring_enter fs/io_uring.c:9301 [inline] [<000000008482e78c>] __x64_sys_io_uring_enter+0xabc/0xc20 fs/io_uring.c:9301 [<00000000b875f18f>] do_syscall_x64 arch/x86/entry/common.c:50 [inline] [<00000000b875f18f>] do_syscall_64+0x3b/0x90 arch/x86/entry/common.c:80 [<000000006b0a8484>] entry_SYSCALL_64_after_hwframe+0x44/0xae CPU0 CPU1 io_uring_enter io_uring_enter io_uring_add_tctx_node io_uring_add_tctx_node __io_uring_add_tctx_node __io_uring_add_tctx_node io_uring_alloc_task_context io_uring_alloc_task_context io_init_wq_offload io_init_wq_offload hash = kzalloc hash = kzalloc ctx->hash_map = hash ctx->hash_map = hash <- one of the hash is leaked When calling io_uring_enter() in parallel, the 'hash_map' will be leaked, add uring_lock to protect 'hash_map'.

UnknownCVSS not scoredNot KEV-listedUpdated
Discuss exposureBack to CVEs
Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

CVE-2021-47292 is a Linux kernel memory leak in io_uring. Parallel calls can leak a small kernel allocation, which may create stability or availability risk if repeatedly triggered. The source bundle does not provide CVSS, CWE, or evidence of active exploitation.

Executive priority

Treat this as a patch-management item for Linux fleets, with higher urgency on multi-tenant or untrusted-workload hosts. It is not KEV-listed and has no provided active exploitation evidence, but kernel availability issues can still affect business operations.

Technical view

The flaw is in io_init_wq_offload() during io_uring task context setup. Concurrent io_uring_enter() paths can allocate and assign ctx->hash_map without locking, leaking one allocation. The cited fix adds uring_lock protection around hash_map initialization.

Likely exposure

Exposure is most relevant to Linux systems running affected kernel versions listed in the source bundle, especially 5.12 through the fixed 5.13.6/5.14 line context, where local processes can use io_uring.

Exploitation context

Evidence comes from a fuzzing memory leak report. The bundle says KEV is false and provides no cited active exploitation. The practical concern is local resource exhaustion or degraded host stability, not remote compromise based on available evidence.

Researcher notes

The source describes a race in hash_map initialization during parallel io_uring_enter() execution. Public data in the bundle is limited: no CVSS, no CWE, and no exploit confirmation. Focus validation on fixed kernel provenance and affected io_uring exposure.

Mitigation direction

  • Update to a vendor kernel containing the cited stable fixes.
  • Check distribution advisories for backported CVE-2021-47292 patches.
  • Prioritize shared hosts and systems running untrusted local workloads.
  • Monitor kernel memory pressure until patched.
  • Do not deploy by raw upstream version alone; verify vendor backports.

Validation and detection

  • Inventory Linux kernel versions across servers and container hosts.
  • Confirm installed kernel changelogs reference CVE-2021-47292 or the cited commits.
  • Identify systems where untrusted users or workloads can call io_uring.
  • Check vulnerability scanner findings against vendor package status.
  • Document any exceptions with compensating monitoring and upgrade dates.
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

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.

cve · low confidence lookup

CVE-2021-47292 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

Open ATT&CK lookup
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

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

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
LinuxLinuxe941894eae31b52f0fd9bdb3ce20620afa152f45, e941894eae31b52f0fd9bdb3ce20620afa152f45unaffected
LinuxLinux5.12, 0, 5.13.6, 5.14affected
Weakness

CWE details

No CWE listed

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.