Vulnerability-Lookup

GHSA-G3V7-Q58W-W9QX

Vulnerability from github – Published: 2024-07-30 09:31 – Updated: 2024-12-19 21:31

Details

In the Linux kernel, the following vulnerability has been resolved:

net: rswitch: Avoid use-after-free in rswitch_poll()

The use-after-free is actually in rswitch_tx_free(), which is inlined in rswitch_poll(). Since skb and gq->skbs[gq->dirty] are in fact the same pointer, the skb is first freed using dev_kfree_skb_any(), then the value in skb->len is used to update the interface statistics.

Let's move around the instructions to use skb->len before the skb is freed.

This bug is trivial to reproduce using KFENCE. It will trigger a splat every few packets. A simple ARP request or ICMP echo request is enough.

Severity

7.8 (High)


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

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{
  "affected": [],
  "aliases": [
    "CVE-2024-42108"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-416"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2024-07-30T08:15:03Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: rswitch: Avoid use-after-free in rswitch_poll()\n\nThe use-after-free is actually in rswitch_tx_free(), which is inlined in\nrswitch_poll(). Since `skb` and `gq-\u003eskbs[gq-\u003edirty]` are in fact the\nsame pointer, the skb is first freed using dev_kfree_skb_any(), then the\nvalue in skb-\u003elen is used to update the interface statistics.\n\nLet\u0027s move around the instructions to use skb-\u003elen before the skb is\nfreed.\n\nThis bug is trivial to reproduce using KFENCE. It will trigger a splat\nevery few packets. A simple ARP request or ICMP echo request is enough.",
  "id": "GHSA-g3v7-q58w-w9qx",
  "modified": "2024-12-19T21:31:08Z",
  "published": "2024-07-30T09:31:51Z",
  "references": [
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      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2024-42108"
    },
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      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/4a41bb9f2b402469d425a1c13359d3b3ea4e6403"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/92cbbe7759193e3418f38d0d73f8fe125312c58b"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/9a0c28efeec6383ef22e97437616b920e7320b67"
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  "severity": [
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}

CVE-2024-42108 (GCVE-0-2024-42108)

Vulnerability from cvelistv5 – Published: 2024-07-30 07:46 – Updated: 2026-08-05 11:35

Title

net: rswitch: Avoid use-after-free in rswitch_poll()

Summary

In the Linux kernel, the following vulnerability has been resolved: net: rswitch: Avoid use-after-free in rswitch_poll() The use-after-free is actually in rswitch_tx_free(), which is inlined in rswitch_poll(). Since `skb` and `gq->skbs[gq->dirty]` are in fact the same pointer, the skb is first freed using dev_kfree_skb_any(), then the value in skb->len is used to update the interface statistics. Let's move around the instructions to use skb->len before the skb is freed. This bug is trivial to reproduce using KFENCE. It will trigger a splat every few packets. A simple ARP request or ICMP echo request is enough.

Severity

9.8 (Critical)


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

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2024-09-10 16:17 UTC

Assigner

Linux CNA under the mitre root

CNA scorecard D 53/100 over 7033 records in the last 180 days details

References

3 references

URL	Tags
https://git.kernel.org/stable/c/4a41bb9f2b402469d…
https://git.kernel.org/stable/c/92cbbe7759193e341…
https://git.kernel.org/stable/c/9a0c28efeec6383ef…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 0aeec4bb6a9fc963932bf3c929bdf27d835d44e9 , < 4a41bb9f2b402469d425a1c13359d3b3ea4e6403 (git) Affected: 271e015b91535dd87fd0f5df0cc3b906c2eddef9 , < 92cbbe7759193e3418f38d0d73f8fe125312c58b (git) Affected: 271e015b91535dd87fd0f5df0cc3b906c2eddef9 , < 9a0c28efeec6383ef22e97437616b920e7320b67 (git)
Linux	Linux	Affected: 6.8 Unaffected: 0 , < 6.8 (semver) Unaffected: 6.9.9 , ≤ 6.9.* (semver) Unaffected: 6.10 , ≤ * (original_commit_for_fix)

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JSON

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              "value": "AV:N - The UAF fires on every hardware TX completion, and an unauthenticated remote host reaches it simply by sending any packet that elicits a reply (ICMP echo request, TCP SYN to a closed port, any service response) \u2014 all routable across L3, not just link-local. The fix commit itself states an ARP or ICMP echo request is sufficient to trigger it.\nAC:L - There is no race, no timing window, and no memory-layout precondition \u2014 `skb-\u003elen` is read unconditionally one statement after `dev_kfree_skb_any()` on every TX-completed skb, and the attacker sets the pace by sending packets. The commit reports a splat \"every few packets,\" so even the KFENCE-guarded-slot case is hit trivially by a sustained flood.\nPR:N - The reply packet is generated by the kernel network stack before any application-layer authentication, so no credentials, session, or account on the target are needed. Recovering the leaked word afterwards requires only a world-readable counter in `/proc/net/dev`.\nUI:N - The attacker sends the packets themselves and the TX-completion NAPI poll runs autonomously; no victim login, mount, file open, or any other action is involved.\nS:U - The use-after-free read, the leaked freelist word, and the resulting fault all stay inside the kernel\u0027s own memory and the rswitch driver\u0027s security authority; no VM, IOMMU, or sandbox boundary is crossed.\nC:H - Because `skbuff_head_cache` has no ctor/RCU/poison flags, SLUB places the freelist pointer at ~offset 112 \u2014 precisely where `skb-\u003elen` sits \u2014 so the freed-memory read pulls the low 32 bits of a kernel heap pointer and adds it into `stats.tx_bytes`, which `rswitch_get_stats()` exports verbatim to `/proc/net/dev` and sysfs. Differencing the counter around a single TX completion recovers that word exactly and repeatably, giving a reliable kernel heap-address/KASLR disclosure; per kernel scoring guidance a use-after-free is High regardless.\nI:H - This is a use-after-free on an object in the general-purpose `skbuff_head_cache`, which per kernel scoring guidance is rated High since freed-object accesses in that cache are the standard primitive for heap grooming and control-flow corruption. Concretely, kernel-maintained interface accounting is corrupted with freed slab contents, poisoning the statistics that monitoring and traffic-accounting decisions rely on.\nA:H - On the many kernels shipping `CONFIG_KFENCE=y` (Android GKI, Fedora, RHEL, Ubuntu, hardened automotive builds) the freed object\u0027s page is unmapped, so the `skb-\u003elen` read page-faults into `kfence_report_error()`, which calls `check_panic_on_warn(\"KFENCE\")` \u2014 an immediate kernel panic on the fail-fast configurations typical for an in-vehicle R-Car S4 gateway. A remote attacker can drive this indefinitely with a ping flood, and any use-after-free is rated High for availability."
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Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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