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CVE Record

CVE-2022-49390: macsec: fix UAF bug for real_dev

In the Linux kernel, the following vulnerability has been resolved: macsec: fix UAF bug for real_dev Create a new macsec device but not get reference to real_dev. That can not ensure that real_dev is freed after macsec. That will trigger the UAF bug for real_dev as following: ================================================================== BUG: KASAN: use-after-free in macsec_get_iflink+0x5f/0x70 drivers/net/macsec.c:3662 Call Trace: ... macsec_get_iflink+0x5f/0x70 drivers/net/macsec.c:3662 dev_get_iflink+0x73/0xe0 net/core/dev.c:637 default_operstate net/core/link_watch.c:42 [inline] rfc2863_policy+0x233/0x2d0 net/core/link_watch.c:54 linkwatch_do_dev+0x2a/0x150 net/core/link_watch.c:161 Allocated by task 22209: ... alloc_netdev_mqs+0x98/0x1100 net/core/dev.c:10549 rtnl_create_link+0x9d7/0xc00 net/core/rtnetlink.c:3235 veth_newlink+0x20e/0xa90 drivers/net/veth.c:1748 Freed by task 8: ... kfree+0xd6/0x4d0 mm/slub.c:4552 kvfree+0x42/0x50 mm/util.c:615 device_release+0x9f/0x240 drivers/base/core.c:2229 kobject_cleanup lib/kobject.c:673 [inline] kobject_release lib/kobject.c:704 [inline] kref_put include/linux/kref.h:65 [inline] kobject_put+0x1c8/0x540 lib/kobject.c:721 netdev_run_todo+0x72e/0x10b0 net/core/dev.c:10327 After commit faab39f63c1f ("net: allow out-of-order netdev unregistration") and commit e5f80fcf869a ("ipv6: give an IPv6 dev to blackhole_netdev"), we can add dev_hold_track() in macsec_dev_init() and dev_put_track() in macsec_free_netdev() to fix the problem.

HighCVSS 7.8Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

This is a Linux kernel memory-safety flaw in MACsec network device handling. A local, low-privileged actor may be able to trigger use-after-free behavior, potentially affecting confidentiality, integrity, and availability. The sources do not show remote exploitation or confirmed active abuse.

Executive priority

High priority for Linux fleets with multi-user access, privileged workloads, or network administration capabilities. Patch through normal urgent kernel maintenance unless vendor guidance indicates broader exposure.

Technical view

The MACsec driver failed to hold a reference to the underlying real_dev when creating a MACsec device. Later link-state processing could dereference freed netdev memory, producing a CWE-416 use-after-free. The documented fix adds dev_hold_track() in macsec_dev_init() and dev_put_track() in macsec_free_netdev().

Likely exposure

Linux systems running affected kernel versions or downstream builds with vulnerable MACsec code are the exposure focus. Risk is highest where untrusted local users or constrained workloads can influence network device creation. Evidence provided does not establish exposure for non-Linux products.

Exploitation context

The CVSS vector is local, low complexity, low privilege, and no user interaction. KEV is false, and the provided sources do not report public exploitation. Treat this as serious kernel hardening work, not as evidence of an internet-facing emergency.

Researcher notes

The source evidence is kernel commit and CVE metadata focused on root cause and fix. It does not provide exploit proof, affected distribution packages, or operational mitigations beyond applying corrected kernel code.

Mitigation direction

  • Apply vendor kernel updates containing the referenced upstream MACsec fixes.
  • Prioritize shared Linux hosts and systems running untrusted local workloads.
  • Check distribution advisories for exact fixed package versions.
  • Use vendor-supported controls if MACsec must be temporarily restricted.

Validation and detection

  • Inventory Linux kernel versions across servers, appliances, and container hosts.
  • Identify systems using MACsec or allowing network device administration by workloads.
  • Compare running kernels against vendor advisories and referenced stable commits.
  • Confirm patched builds include the real_dev reference-counting fix.
Prepared
Confidence
high
Sources
5

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

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cwe · low confidence lookup

CWE-416: Exact CWE lookup

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Open ATT&CK lookup
cve · low confidence lookup

CVE-2022-49390 mapping review

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Vulnerability profileCVE Program record
Severity
High
CVSS
7.8 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/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
4Source links

SSVC decision data

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

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
7.8CVSS 3.1HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H1.85.9CISA-ADP

Vulnerability scoring details

Base CVSS 3.1 score

7.8High
CVSS 3.1 vector shape for CVE-2022-49390Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/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
LinuxLinux2bce1ebed17da54c65042ec2b962e3234bad5b47, 2bce1ebed17da54c65042ec2b962e3234bad5b47, 2bce1ebed17da54c65042ec2b962e3234bad5b47, 1861904a6092ed411203c6a02c75bfc45b27cc3c, 3a2675a2d97a68332fa5c33043038bfeb31455a8, b0add6db3d5ec4561cab257358871a9d3df7f0a3unaffected
LinuxLinux5.4, 0, 5.17.15, 5.18.3, 5.19affected
Weakness

CWE details

CWE-416

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

CWE-416 · source CWE mapping

Use After Free

Use After Free represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

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