CVE-2026-98052 (GCVE-0-2026-98052)

Vulnerability from cvelistv5 – Published: 2026-09-25 10:24 – Updated: 2026-09-25 14:41
VLAI
Title
net: bcmasp: clear txcb->last before writing each descriptor
Summary
In the Linux kernel, the following vulnerability has been resolved: net: bcmasp: clear txcb->last before writing each descriptor bcmasp_xmit() only wrote txcb->last = true for the final fragment of an SKB; non-final fragments left the field untouched. If a descriptor slot was reused while it still held a stale true from a previous SKB (possible when tx_spb_ring_full() underreported fullness), bcmasp_tx_reclaim() would see last == true mid-SKB and call dev_consume_skb_any() prematurely, freeing the sk_buff while its remaining fragments were still in flight. Unconditionally clear txcb->last before the conditional set so every descriptor slot starts from a known false state regardless of what a prior transmission left behind.
Severity
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 490cb412007de593e07c1d3e2b1ec4233886707c , < 9b26b54861ce05307d39a54ddedddf8747419614 (git)
Affected: 490cb412007de593e07c1d3e2b1ec4233886707c , < 47a5cecca925ceb175d5adf712e667acf78f475f (git)
Affected: 490cb412007de593e07c1d3e2b1ec4233886707c , < 17e6ad484dea5ddf1c4a3d6ec77a5929161234de (git)
Affected: 490cb412007de593e07c1d3e2b1ec4233886707c , < 18e5e0ec0e9282c897e2aa81a3e43ccaee03b003 (git)
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Linux Linux Affected: 6.6
Unaffected: 0 , < 6.6 (semver)
Unaffected: 6.12.111 , ≤ 6.12.* (semver)
Unaffected: 6.18.53 , ≤ 6.18.* (semver)
Unaffected: 7.2.7 , ≤ 7.2.* (semver)
Unaffected: 7.3-rc3 , ≤ * (original_commit_for_fix)
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{
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      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/net/ethernet/broadcom/asp2/bcmasp_intf.c"
          ],
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          "vendor": "Linux",
          "versions": [
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              "versionType": "semver"
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              "operator": "OR"
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          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: bcmasp: clear txcb-\u003elast before writing each descriptor\n\nbcmasp_xmit() only wrote txcb-\u003elast = true for the final fragment\nof an SKB; non-final fragments left the field untouched.  If a\ndescriptor slot was reused while it still held a stale true from\na previous SKB (possible when tx_spb_ring_full() underreported\nfullness), bcmasp_tx_reclaim() would see last == true mid-SKB and\ncall dev_consume_skb_any() prematurely, freeing the sk_buff while\nits remaining fragments were still in flight.\n\nUnconditionally clear txcb-\u003elast before the conditional set so every\ndescriptor slot starts from a known false state regardless of what a\nprior transmission left behind."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
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              "lang": "en",
              "value": "AV:L - The bug is in bcmasp_xmit() TX ring bookkeeping, reached via sendmsg/sendfile -\u003e dev_queue_xmit -\u003e bcmasp_xmit; no malformed input exists and the trigger is TX ring pressure from multi-fragment (NETIF_F_SG) SKBs, which a local user produces by flooding sockets through the bcmasp interface.\nAC:L - The attacker controls the traffic load: flooding multi-frag SKBs makes buggy tx_spb_ring_full() let bcmasp_xmit overwrite unreclaimed slots, so non-final fragments repeatedly land in slots holding a stale txcb-\u003elast=true; no hardware state outside the attacker\u0027s control is needed.\nPR:L - Sending TCP/UDP traffic that egresses the bcmasp netdev needs only an ordinary unprivileged local account; there is no capability check anywhere on the transmit path.\nUI:N - No victim action is involved; the attacker generates the transmit traffic entirely by themselves.\nS:U - The corruption affects kernel sk_buff/page memory in the same kernel that runs the driver; no VM or IOMMU boundary is crossed.\nC:H - bcmasp_tx_reclaim() frees the skb (dev_consume_skb_any) while its later fragments are still mapped for DMA, so freed and reallocated pages can be transmitted on the wire and the stale skb is accessed again: a use-after-free with disclosure potential.\nI:H - When the real final fragment is reclaimed later, dev_consume_skb_any() is called a second time on the same skb, a double free/UAF of sk_buff and frag pages that could be groomed into slab corruption.\nA:H - Double freeing the sk_buff and touching freed memory in bcmasp_tx_reclaim() from TX NAPI causes slab corruption and kernel oops/panic on the host."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-25T14:41:58.081Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
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      "title": "net: bcmasp: clear txcb-\u003elast before writing each descriptor",
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-98052",
    "datePublished": "2026-09-25T10:24:00.441Z",
    "dateReserved": "2026-09-25T10:19:56.072Z",
    "dateUpdated": "2026-09-25T14:41:58.081Z",
    "state": "PUBLISHED"
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      "date": "2026-09-27",
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      "percentile": "0.02096"
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                ],
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        "descriptions": [
          {
            "lang": "en",
            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: bcmasp: clear txcb-\u003elast before writing each descriptor\n\nbcmasp_xmit() only wrote txcb-\u003elast = true for the final fragment\nof an SKB; non-final fragments left the field untouched.  If a\ndescriptor slot was reused while it still held a stale true from\na previous SKB (possible when tx_spb_ring_full() underreported\nfullness), bcmasp_tx_reclaim() would see last == true mid-SKB and\ncall dev_consume_skb_any() prematurely, freeing the sk_buff while\nits remaining fragments were still in flight.\n\nUnconditionally clear txcb-\u003elast before the conditional set so every\ndescriptor slot starts from a known false state regardless of what a\nprior transmission left behind."
          }
        ],
        "id": "CVE-2026-98052",
        "lastModified": "2026-09-25T15:18:05.023",
        "metrics": {
          "cvssMetricV31": [
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                "confidentialityImpact": "HIGH",
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                "privilegesRequired": "LOW",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
                "version": "3.1"
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              "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
              "type": "Secondary"
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        "published": "2026-09-25T11:17:34.120",
        "references": [
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        ],
        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Received"
      }
    }
  }
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

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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.



Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.