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CVE Record

CVE-2024-35839: netfilter: bridge: replace physindev with physinif in nf_bridge_info

In the Linux kernel, the following vulnerability has been resolved: netfilter: bridge: replace physindev with physinif in nf_bridge_info An skb can be added to a neigh->arp_queue while waiting for an arp reply. Where original skb's skb->dev can be different to neigh's neigh->dev. For instance in case of bridging dnated skb from one veth to another, the skb would be added to a neigh->arp_queue of the bridge. As skb->dev can be reset back to nf_bridge->physindev and used, and as there is no explicit mechanism that prevents this physindev from been freed under us (for instance neigh_flush_dev doesn't cleanup skbs from different device's neigh queue) we can crash on e.g. this stack: arp_process neigh_update skb = __skb_dequeue(&neigh->arp_queue) neigh_resolve_output(..., skb) ... br_nf_dev_xmit br_nf_pre_routing_finish_bridge_slow skb->dev = nf_bridge->physindev br_handle_frame_finish Let's use plain ifindex instead of net_device link. To peek into the original net_device we will use dev_get_by_index_rcu(). Thus either we get device and are safe to use it or we don't get it and drop skb.

HighCVSS 7.8Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

A Linux networking flaw can leave a stale device reference when bridged traffic waits for ARP resolution. Reusing that reference may crash the kernel. The supplied CVSS score is 7.8, but exploitation requires local, low-privileged access and specific bridge networking conditions.

Executive priority

Prioritize remediation for exposed container, virtualization, and bridging infrastructure, where a kernel crash could disrupt multiple workloads. Treat ordinary Linux endpoints as lower urgency until networking configuration and vendor patch status are confirmed. No active exploitation is established by the supplied evidence.

Technical view

Netfilter bridge metadata retains physindev as a net_device pointer while an skb may remain on another device’s neighbour ARP queue. The device can be freed before later reuse, creating a stale-reference condition. Stable fixes store the interface index and retrieve the device safely with dev_get_by_index_rcu(), dropping the skb if unavailable.

Likely exposure

Exposure is most plausible on affected Linux kernels using bridge netfilter with bridged, DNATed, veth, and delayed ARP-resolution traffic. The supplied affected-version data is ambiguous and should not be treated as a complete distribution-specific inventory.

Exploitation context

The CVSS vector describes local attack access, low privileges, low complexity, and no user interaction. The supplied sources do not establish active exploitation, and the CVE is not listed as KEV in the bundle. Evidence supports a kernel-crash scenario; broader impact is represented by CVSS but not demonstrated here.

Researcher notes

The core issue is unsafe lifetime handling of nf_bridge_info.physindev across neighbour queueing. The fix replaces the device pointer with an interface index and performs an RCU lookup before reuse. The bundle provides stable commit references but insufficient distribution-specific package mapping or complete affected-range semantics.

Mitigation direction

  • Install a supported vendor kernel containing the applicable stable fix.
  • Match deployed kernel branches against the four referenced Linux stable commits.
  • Prioritize bridge, container, virtualization, and network-gateway hosts using netfilter.
  • Check distribution security advisories before applying version-specific remediation.

Validation and detection

  • Inventory kernel versions across Linux hosts and container nodes.
  • Determine whether bridge netfilter, veth networking, DNAT, and bridging are used.
  • Verify the applicable stable fix exists in each running kernel package.
  • Review kernel logs for crashes involving ARP, neighbour resolution, or bridge netfilter paths.
  • Reboot patched systems and confirm the corrected kernel is running.
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

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.

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CVE-2024-35839 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
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
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-2024-35839Attack 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
LinuxLinuxc4e70a87d975d1f561a00abfe2d3cefa2a486c95, c4e70a87d975d1f561a00abfe2d3cefa2a486c95, c4e70a87d975d1f561a00abfe2d3cefa2a486c95, c4e70a87d975d1f561a00abfe2d3cefa2a486c95unaffected
LinuxLinux4.2, 0, 6.1.75, 6.6.14, 6.7.2, 6.8affected
Weakness

CWE details

No CWE listed

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