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CVE Record

CVE-2023-53441: bpf: cpumap: Fix memory leak in cpu_map_update_elem

In the Linux kernel, the following vulnerability has been resolved: bpf: cpumap: Fix memory leak in cpu_map_update_elem Syzkaller reported a memory leak as follows: BUG: memory leak unreferenced object 0xff110001198ef748 (size 192): comm "syz-executor.3", pid 17672, jiffies 4298118891 (age 9.906s) hex dump (first 32 bytes): 00 00 00 00 4a 19 00 00 80 ad e3 e4 fe ff c0 00 ....J........... 00 b2 d3 0c 01 00 11 ff 28 f5 8e 19 01 00 11 ff ........(....... backtrace: [<ffffffffadd28087>] __cpu_map_entry_alloc+0xf7/0xb00 [<ffffffffadd28d8e>] cpu_map_update_elem+0x2fe/0x3d0 [<ffffffffadc6d0fd>] bpf_map_update_value.isra.0+0x2bd/0x520 [<ffffffffadc7349b>] map_update_elem+0x4cb/0x720 [<ffffffffadc7d983>] __se_sys_bpf+0x8c3/0xb90 [<ffffffffb029cc80>] do_syscall_64+0x30/0x40 [<ffffffffb0400099>] entry_SYSCALL_64_after_hwframe+0x61/0xc6 BUG: memory leak unreferenced object 0xff110001198ef528 (size 192): comm "syz-executor.3", pid 17672, jiffies 4298118891 (age 9.906s) hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace: [<ffffffffadd281f0>] __cpu_map_entry_alloc+0x260/0xb00 [<ffffffffadd28d8e>] cpu_map_update_elem+0x2fe/0x3d0 [<ffffffffadc6d0fd>] bpf_map_update_value.isra.0+0x2bd/0x520 [<ffffffffadc7349b>] map_update_elem+0x4cb/0x720 [<ffffffffadc7d983>] __se_sys_bpf+0x8c3/0xb90 [<ffffffffb029cc80>] do_syscall_64+0x30/0x40 [<ffffffffb0400099>] entry_SYSCALL_64_after_hwframe+0x61/0xc6 BUG: memory leak unreferenced object 0xff1100010fd93d68 (size 8): comm "syz-executor.3", pid 17672, jiffies 4298118891 (age 9.906s) hex dump (first 8 bytes): 00 00 00 00 00 00 00 00 ........ backtrace: [<ffffffffade5db3e>] kvmalloc_node+0x11e/0x170 [<ffffffffadd28280>] __cpu_map_entry_alloc+0x2f0/0xb00 [<ffffffffadd28d8e>] cpu_map_update_elem+0x2fe/0x3d0 [<ffffffffadc6d0fd>] bpf_map_update_value.isra.0+0x2bd/0x520 [<ffffffffadc7349b>] map_update_elem+0x4cb/0x720 [<ffffffffadc7d983>] __se_sys_bpf+0x8c3/0xb90 [<ffffffffb029cc80>] do_syscall_64+0x30/0x40 [<ffffffffb0400099>] entry_SYSCALL_64_after_hwframe+0x61/0xc6 In the cpu_map_update_elem flow, when kthread_stop is called before calling the threadfn of rcpu->kthread, since the KTHREAD_SHOULD_STOP bit of kthread has been set by kthread_stop, the threadfn of rcpu->kthread will never be executed, and rcpu->refcnt will never be 0, which will lead to the allocated rcpu, rcpu->queue and rcpu->queue->queue cannot be released. Calling kthread_stop before executing kthread's threadfn will return -EINTR. We can complete the release of memory resources in this state.

MediumCVSS 5.5Not KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

CVE-2023-53441 is a Linux kernel memory leak in the BPF CPU map update path. A local user with the needed BPF privileges could trigger unreleased memory and cause availability impact. The record rates it medium, with high availability impact and no confidentiality or integrity impact stated.

Executive priority

Treat this as a routine but real availability risk for Linux fleets, especially shared or multi-tenant systems. Prioritize patching through normal kernel maintenance windows, with faster action where untrusted local workloads or privileged containers can access BPF.

Technical view

The flaw is CWE-401 in cpu_map_update_elem. If kthread_stop occurs before the cpumap kthread thread function runs, rcpu->refcnt never reaches zero, leaving rcpu, rcpu->queue, and rcpu->queue->queue allocated. Stable kernel commits implement cleanup when kthread_stop returns -EINTR.

Likely exposure

Exposure is mainly Linux systems running affected kernel versions or affected downstream backports where local users, services, or containers can exercise BPF map update functionality. Internet exposure is not indicated because the CVSS vector is local and requires low privileges.

Exploitation context

The source bundle does not cite active exploitation, and KEV is false. Evidence is from Syzkaller memory-leak reporting and kernel fix commits, not public exploitation. Abuse would require local access and relevant BPF capability or policy allowance.

Researcher notes

The CVE describes a memory leak in the BPF cpumap allocation path, reported by Syzkaller. The fix centers on cleanup after an early kthread_stop return of -EINTR. The bundle provides fix commits but does not provide exploit telemetry or downstream package mapping.

Mitigation direction

  • Update to a vendor-supported kernel containing the listed stable fixes.
  • Check distribution advisories for the exact fixed package version.
  • Restrict untrusted local access to BPF features where operationally feasible.
  • Reduce unnecessary privileged container capabilities related to BPF.
  • Monitor for unexplained kernel memory growth on exposed multi-user systems.

Validation and detection

  • Inventory Linux kernel versions across servers, endpoints, and container hosts.
  • Confirm the relevant stable commit or vendor backport is present.
  • Review which users, services, or containers can use BPF functionality.
  • Correlate local privilege boundaries with systems running affected kernels.
  • Use vendor scanners or package metadata to verify remediation status.
Prepared
Confidence
high
Sources
6

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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ATT&CK lookup starting points

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cwe · low confidence lookup

CWE-401: Exact CWE lookup

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cve · low confidence lookup

CVE-2023-53441 mapping review

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Vulnerability profileCVE Program record
Severity
Medium
CVSS
5.5 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

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.

1CVSS vectors
3Timeline events
1ADP providers
5Source links

SSVC decision data

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

CVSS vector scores

1 official score

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
5.5CVSS 3.1MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H1.83.6CISA-ADP

Vulnerability scoring details

Base CVSS 3.1 score

5.5Medium
CVSS 3.1 vector shape for CVE-2023-53441Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

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
cvssV3_1other:ssvc

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinux6710e1126934d8b4372b4d2f9ae1646cd3f151bf, 6710e1126934d8b4372b4d2f9ae1646cd3f151bf, 6710e1126934d8b4372b4d2f9ae1646cd3f151bf, 6710e1126934d8b4372b4d2f9ae1646cd3f151bfunaffected
LinuxLinux4.15, 0, 5.15.121, 6.1.40, 6.4.5, 6.5affected
Weakness

CWE details

CWE-401

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

CWE-401 · source CWE mapping

Missing Release of Memory after Effective Lifetime

Missing Release of Memory after Effective Lifetime represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

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