Vulnerability-Lookup

GHSA-3R27-V3Q5-PHCC

Vulnerability from github – Published: 2026-09-11 21:31 – Updated: 2026-09-14 15:32

Details

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

net/smc: unregister the connection before draining the rx tasklet

smc_conn_free() calls smc_ism_unset_conn() only while the link group is still on its device list, and never sets conn->killed. smc_lgr_terminate_sched() unlinks the group immediately and defers killing its connections to a work item, so a connection freed in that window keeps its smcd->conn[] slot with both gates in smcd_handle_irq() open, and the device can re-arm the receive tasklet after tasklet_kill() has returned. On the DMB-nocopy path the ghost send buffer is freed right after that drain, so the re-armed tasklet dereferences it.

Unregister unconditionally and drain before the detach at both teardown sites, mirroring rmb_desc, which smc_buf_unuse() releases after the drain. Clear conn->sndbuf_desc before freeing it as well, so a reader that samples the pointer cannot get one that is already freed.

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-2026-80979"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-09-11T20:19:04Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/smc: unregister the connection before draining the rx tasklet\n\nsmc_conn_free() calls smc_ism_unset_conn() only while the link group is\nstill on its device list, and never sets conn-\u003ekilled.\nsmc_lgr_terminate_sched() unlinks the group immediately and defers killing\nits connections to a work item, so a connection freed in that window keeps\nits smcd-\u003econn[] slot with both gates in smcd_handle_irq() open, and the\ndevice can re-arm the receive tasklet after tasklet_kill() has returned. On\nthe DMB-nocopy path the ghost send buffer is freed right after that drain,\nso the re-armed tasklet dereferences it.\n\nUnregister unconditionally and drain before the detach at both teardown\nsites, mirroring rmb_desc, which smc_buf_unuse() releases after the drain.\nClear conn-\u003esndbuf_desc before freeing it as well, so a reader that samples\nthe pointer cannot get one that is already freed.",
  "id": "GHSA-3r27-v3q5-phcc",
  "modified": "2026-09-14T15:32:21Z",
  "published": "2026-09-11T21:31:22Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-80979"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/36cdf5d48ca191dcd71c28cadbe0981b1d25318d"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/5bd8b764a610b6b6bc0c4d3d01652747f6e0b5c3"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/b4d540ac95cd35c6ebab6afb7eae2bcac7b277a5"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/b6b6ac713ee82b340a8e3be30b101bd2840deec4"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/b74d313567dfc1b7e56629ddbad04e728686f235"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2026-80979 (GCVE-0-2026-80979)

Vulnerability from cvelistv5 – Published: 2026-09-11 19:42 – Updated: 2026-09-14 11:59

Title

net/smc: unregister the connection before draining the rx tasklet

Summary

In the Linux kernel, the following vulnerability has been resolved: net/smc: unregister the connection before draining the rx tasklet smc_conn_free() calls smc_ism_unset_conn() only while the link group is still on its device list, and never sets conn->killed. smc_lgr_terminate_sched() unlinks the group immediately and defers killing its connections to a work item, so a connection freed in that window keeps its smcd->conn[] slot with both gates in smcd_handle_irq() open, and the device can re-arm the receive tasklet after tasklet_kill() has returned. On the DMB-nocopy path the ghost send buffer is freed right after that drain, so the re-armed tasklet dereferences it. Unregister unconditionally and drain before the detach at both teardown sites, mirroring rmb_desc, which smc_buf_unuse() releases after the drain. Clear conn->sndbuf_desc before freeing it as well, so a reader that samples the pointer cannot get one that is already freed.

Severity

7.8 (High)


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

Assigner

Linux mitre root

References

5 references

URL	Tags
https://git.kernel.org/stable/c/b6b6ac713ee82b340…
https://git.kernel.org/stable/c/b4d540ac95cd35c6e…
https://git.kernel.org/stable/c/5bd8b764a610b6b6b…
https://git.kernel.org/stable/c/b74d313567dfc1b7e…
https://git.kernel.org/stable/c/36cdf5d48ca191dcd…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 21f6f41e82e59740e26e06e77bdf58dc7f6f08dd , < b6b6ac713ee82b340a8e3be30b101bd2840deec4 (git) Affected: ae2be35cbed2c8385e890147ea321a3fcc3ca5fa , < b4d540ac95cd35c6ebab6afb7eae2bcac7b277a5 (git) Affected: ae2be35cbed2c8385e890147ea321a3fcc3ca5fa , < 5bd8b764a610b6b6bc0c4d3d01652747f6e0b5c3 (git) Affected: ae2be35cbed2c8385e890147ea321a3fcc3ca5fa , < b74d313567dfc1b7e56629ddbad04e728686f235 (git) Affected: ae2be35cbed2c8385e890147ea321a3fcc3ca5fa , < 36cdf5d48ca191dcd71c28cadbe0981b1d25318d (git) Affected: 6.6.66 , < 6.6.157 (semver)
Linux	Linux	Affected: 6.10 Unaffected: 0 , < 6.10 (semver) Unaffected: 6.6.157 , ≤ 6.6.* (semver) Unaffected: 6.12.109 , ≤ 6.12.* (semver) Unaffected: 6.18.50 , ≤ 6.18.* (semver) Unaffected: 7.2.4 , ≤ 7.2.* (semver) Unaffected: 7.3-rc1 , ≤ * (original_commit_for_fix)

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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/smc/smc_core.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
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            {
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              "status": "affected",
              "version": "21f6f41e82e59740e26e06e77bdf58dc7f6f08dd",
              "versionType": "git"
            },
            {
              "lessThan": "b4d540ac95cd35c6ebab6afb7eae2bcac7b277a5",
              "status": "affected",
              "version": "ae2be35cbed2c8385e890147ea321a3fcc3ca5fa",
              "versionType": "git"
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              "status": "affected",
              "version": "ae2be35cbed2c8385e890147ea321a3fcc3ca5fa",
              "versionType": "git"
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              "status": "affected",
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            },
            {
              "lessThan": "36cdf5d48ca191dcd71c28cadbe0981b1d25318d",
              "status": "affected",
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              "versionType": "git"
            },
            {
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              "status": "affected",
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            }
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          "product": "Linux",
          "programFiles": [
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          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.10"
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              "status": "unaffected",
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              "versionType": "semver"
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              "status": "unaffected",
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              "versionType": "semver"
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              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.109",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.50",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.4",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3-rc1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.109",
                  "versionStartIncluding": "6.10",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.50",
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                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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              ],
              "negate": false,
              "operator": "OR"
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      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/smc: unregister the connection before draining the rx tasklet\n\nsmc_conn_free() calls smc_ism_unset_conn() only while the link group is\nstill on its device list, and never sets conn-\u003ekilled.\nsmc_lgr_terminate_sched() unlinks the group immediately and defers killing\nits connections to a work item, so a connection freed in that window keeps\nits smcd-\u003econn[] slot with both gates in smcd_handle_irq() open, and the\ndevice can re-arm the receive tasklet after tasklet_kill() has returned. On\nthe DMB-nocopy path the ghost send buffer is freed right after that drain,\nso the re-armed tasklet dereferences it.\n\nUnregister unconditionally and drain before the detach at both teardown\nsites, mirroring rmb_desc, which smc_buf_unuse() releases after the drain.\nClear conn-\u003esndbuf_desc before freeing it as well, so a reader that samples\nthe pointer cannot get one that is already freed."
        }
      ],
      "metrics": [
        {
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            "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": [
            {
              "lang": "en",
              "value": "AV:L - The UAF is on the SMC-D DMB-nocopy teardown path, which only loopback-ISM implements; that device accepts a peer only when the GID matches this host, so a local AF_SMC/IPPROTO_SMC pair reaches smc_conn_free()/smcd_handle_irq(), and a remote TCP/CLC peer cannot attach to that fabric.\nAC:L - The attacker owns both sockets and can send on one endpoint to arm smcd_handle_irq() while close() on the other runs smc_conn_free()/smc_conn_kill, which kfree sndbuf_desc before tasklet_kill; they control both sides of the race, so complexity is Low.\nPR:L - socket(AF_SMC) and IPPROTO_SMC listen/connect on ephemeral ports need no capabilities, and loopback-ISM is usable from a user network namespace, so only an unprivileged local account is required.\nUI:N - The attacker performs connect, send, and close on their own SMC sockets; no separate victim action such as mounting a filesystem or opening a file is required.\nS:U - The freed object is a kernel kmalloc smc_buf_desc processed by a tasklet in the same kernel; this is privilege escalation within one security authority, not a VM, IOMMU, or sandbox escape.\nC:H - smcd_cdc_rx_tsklet/smc_cdc_msg_recv_action dereference the freed ghost sndbuf_desc (including -\u003elen); a slab use-after-free of a kmalloc object that the attacker can spray yields an arbitrary kernel read.\nI:H - The same tasklet continues into cursor updates and smc_tx_pending() which write through the recycled descriptor, so heap spraying the use-after-free provides an arbitrary kernel write and control-flow hijack primitive.\nA:H - Tasklet use of the freed smc_buf_desc oopses or panics the kernel even without a full exploit, causing a full system availability loss that the attacker can repeat."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-14T11:59:24.610Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/b6b6ac713ee82b340a8e3be30b101bd2840deec4"
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          "url": "https://git.kernel.org/stable/c/b4d540ac95cd35c6ebab6afb7eae2bcac7b277a5"
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          "url": "https://git.kernel.org/stable/c/5bd8b764a610b6b6bc0c4d3d01652747f6e0b5c3"
        },
        {
          "url": "https://git.kernel.org/stable/c/b74d313567dfc1b7e56629ddbad04e728686f235"
        },
        {
          "url": "https://git.kernel.org/stable/c/36cdf5d48ca191dcd71c28cadbe0981b1d25318d"
        }
      ],
      "title": "net/smc: unregister the connection before draining the rx tasklet",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-80979",
    "datePublished": "2026-09-11T19:42:40.171Z",
    "dateReserved": "2026-08-26T14:34:25.811Z",
    "dateUpdated": "2026-09-14T11:59:24.610Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

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.

Detection rules are retrieved from Rulezet.

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.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

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