CVE-2026-80979 (GCVE-0-2026-80979)
Vulnerability from cvelistv5
Published
2026-09-11 19:42
Modified
2026-10-19 08:46
Severity ?
7.8 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
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.
References
Impacted products
Vendor Product Version
Linux Linux Version: 21f6f41e82e59740e26e06e77bdf58dc7f6f08dd
Version: ae2be35cbed2c8385e890147ea321a3fcc3ca5fa
Version: ae2be35cbed2c8385e890147ea321a3fcc3ca5fa
Version: ae2be35cbed2c8385e890147ea321a3fcc3ca5fa
Version: ae2be35cbed2c8385e890147ea321a3fcc3ca5fa
Version: 6.6.66   ≤
Create a notification for this product.
Show details on NVD website

To clipboard 

{
  "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",
          "versions": [
            {
              "lessThan": "b6b6ac713ee82b340a8e3be30b101bd2840deec4",
              "status": "affected",
              "version": "21f6f41e82e59740e26e06e77bdf58dc7f6f08dd",
              "versionType": "git"
            },
            {
              "lessThan": "b4d540ac95cd35c6ebab6afb7eae2bcac7b277a5",
              "status": "affected",
              "version": "ae2be35cbed2c8385e890147ea321a3fcc3ca5fa",
              "versionType": "git"
            },
            {
              "lessThan": "5bd8b764a610b6b6bc0c4d3d01652747f6e0b5c3",
              "status": "affected",
              "version": "ae2be35cbed2c8385e890147ea321a3fcc3ca5fa",
              "versionType": "git"
            },
            {
              "lessThan": "b74d313567dfc1b7e56629ddbad04e728686f235",
              "status": "affected",
              "version": "ae2be35cbed2c8385e890147ea321a3fcc3ca5fa",
              "versionType": "git"
            },
            {
              "lessThan": "36cdf5d48ca191dcd71c28cadbe0981b1d25318d",
              "status": "affected",
              "version": "ae2be35cbed2c8385e890147ea321a3fcc3ca5fa",
              "versionType": "git"
            },
            {
              "lessThan": "6.6.157",
              "status": "affected",
              "version": "6.6.66",
              "versionType": "semver"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/smc/smc_core.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.10"
            },
            {
              "lessThan": "6.10",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.157",
              "versionType": "semver"
            },
            {
              "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",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.157",
                  "versionStartIncluding": "6.6.66",
                  "vulnerable": true
                },
                {
                  "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",
                  "versionStartIncluding": "6.10",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2.4",
                  "versionStartIncluding": "6.10",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3",
                  "versionStartIncluding": "6.10",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "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": [
        {
          "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": [
            {
              "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": "2026-10-19T08:46:03.770Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/b6b6ac713ee82b340a8e3be30b101bd2840deec4"
        },
        {
          "url": "https://git.kernel.org/stable/c/b4d540ac95cd35c6ebab6afb7eae2bcac7b277a5"
        },
        {
          "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": "2026-10-19T08:46:03.770Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


Log in or create an account to share your comment.




Tags
Taxonomy of the tags.




Sightings

Author Source Type Date

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
  • Confirmed: The vulnerability is confirmed from an analyst perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
  • Patched: This vulnerability was successfully patched by the user reporting the sighting.
  • Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
  • Not confirmed: The user expresses doubt about the veracity of the vulnerability.
  • Not patched: This vulnerability was not successfully patched by the user reporting the sighting.