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CVE Record

CVE-2024-46800: sch/netem: fix use after free in netem_dequeue

In the Linux kernel, the following vulnerability has been resolved: sch/netem: fix use after free in netem_dequeue If netem_dequeue() enqueues packet to inner qdisc and that qdisc returns __NET_XMIT_STOLEN. The packet is dropped but qdisc_tree_reduce_backlog() is not called to update the parent's q.qlen, leading to the similar use-after-free as Commit e04991a48dbaf382 ("netem: fix return value if duplicate enqueue fails") Commands to trigger KASAN UaF: ip link add type dummy ip link set lo up ip link set dummy0 up tc qdisc add dev lo parent root handle 1: drr tc filter add dev lo parent 1: basic classid 1:1 tc class add dev lo classid 1:1 drr tc qdisc add dev lo parent 1:1 handle 2: netem tc qdisc add dev lo parent 2: handle 3: drr tc filter add dev lo parent 3: basic classid 3:1 action mirred egress redirect dev dummy0 tc class add dev lo classid 3:1 drr ping -c1 -W0.01 localhost # Trigger bug tc class del dev lo classid 1:1 tc class add dev lo classid 1:1 drr ping -c1 -W0.01 localhost # UaF

HighCVSS 7.8Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

CVE-2024-46800 is a Linux kernel memory-safety flaw in the netem network-emulation scheduler. A specially arranged local traffic-control configuration can leave incorrect queue state and cause use-after-free access. The supplied CVSS score is 7.8, reflecting potentially serious confidentiality, integrity, and availability impact, but the issue is not remotely reachable by itself.

Executive priority

Treat this as a high-priority kernel maintenance issue, especially on multi-user or multi-tenant hosts with delegated networking capabilities. It is not evidence of an internet-wide emergency: exploitation requires local access and specific traffic-control conditions, and the supplied sources do not establish active attacks.

Technical view

When netem_dequeue() passes a packet to an inner queueing discipline that returns __NET_XMIT_STOLEN, the packet is dropped without reducing the parent backlog. The resulting stale q.qlen state can later produce a use-after-free. The disclosure demonstrates detection with KASAN and identifies stable-kernel commits resolving the accounting error.

Likely exposure

Exposure is concentrated on affected Linux kernels where a local, low-privileged principal can influence the relevant traffic-control and nested qdisc configuration. Internet exposure alone does not establish vulnerability because the CVSS attack vector is local. The supplied affected-version data is not sufficiently clear for reliable branch-by-branch decisions; verify against distribution guidance and fix commits.

Exploitation context

The source bundle does not report active exploitation, and this CVE is not identified as CISA KEV. Public technical details include a KASAN reproducer, but they demonstrate the memory error rather than confirmed real-world compromise.

Researcher notes

The demonstrated defect is incorrect parent queue-length accounting after an inner qdisc reports a stolen transmission. The supplied CVSS vector is AV:L/AC:L/PR:L/UI:N with high impact across confidentiality, integrity, and availability. The evidence confirms a KASAN-detected use-after-free; it does not establish a weaponized exploit or observed privilege escalation.

Mitigation direction

  • Upgrade to a vendor-supported kernel release containing the applicable upstream stable fix.
  • Follow distribution security guidance, including the referenced Debian advisories where applicable.
  • Prioritize exposed multi-user or multi-tenant systems permitting local traffic-control administration.
  • Reboot after upgrading so the fixed kernel is actually running.

Validation and detection

  • Inventory running kernel releases on systems using Linux traffic-control features.
  • Compare each kernel against vendor CVE guidance and the applicable stable fix commit.
  • Review which local users or workloads can administer traffic-control configurations.
  • After remediation, confirm the running kernel matches the installed fixed release.
  • Avoid reproducing the disclosed use-after-free procedure on production systems.
Prepared
Confidence
medium
Sources
12

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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CVE-2024-46800 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
2ADP providers
11Source 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
7.8CVSS 3.1HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H1.85.9Linux

Vulnerability scoring details

Base CVSS 3.1 score

7.8High
CVSS 3.1 vector shape for CVE-2024-46800Attack 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
other:ssvc
CVECVE Program Container

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinux50612537e9ab29693122fab20fc1eed235054ffe, 50612537e9ab29693122fab20fc1eed235054ffe, 50612537e9ab29693122fab20fc1eed235054ffe, 50612537e9ab29693122fab20fc1eed235054ffe, 50612537e9ab29693122fab20fc1eed235054ffe, 50612537e9ab29693122fab20fc1eed235054ffe, 50612537e9ab29693122fab20fc1eed235054ffe, 50612537e9ab29693122fab20fc1eed235054ffeunaffected
LinuxLinux3.3, 0, 4.19.322, 5.4.284, 5.10.226, 5.15.167, 6.1.110, 6.6.51, 6.10.10, 6.11affected
Weakness

CWE details

No CWE listed

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