CVE-2026-63955 (GCVE-0-2026-63955)

Vulnerability from cvelistv5 – Published: 2026-07-19 14:55 – Updated: 2026-07-20 13:41
VLAI
Title
mm/vmalloc: do not trigger BUG() on BH disabled context
Summary
In the Linux kernel, the following vulnerability has been resolved: mm/vmalloc: do not trigger BUG() on BH disabled context __get_vm_area_node() currently triggers a BUG() if in_interrupt() returns true. However, in_interrupt() also reports true when BH are disabled. The bridge code can call rhashtable_lookup_insert_fast() with bottom halves disabled: __vlan_add() -> br_fdb_add_local() spin_lock_bh(&br->hash_lock); <-- Disable BH -> fdb_add_local() -> fdb_create() -> rhashtable_lookup_insert_fast() -> kvmalloc() -> vmalloc() -> __get_vm_area_node() -> BUG_ON(in_interrupt()) spin_unlock_bh(&br->hash_lock) this triggers the BUG() despite the caller not being in NMI or hard IRQ context. Replace the in_interrupt() check with in_nmi() || in_hardirq().
Severity
7.5 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: c6307674ed82c0c57d6e1e3408e84ac449ab8e94 , < ad7eff07b625f53c3fb513b30d7a8c5a79fbc7ce (git)
Affected: c6307674ed82c0c57d6e1e3408e84ac449ab8e94 , < 04aa71da5f35aacdc9ae9cb5150947daa624f641 (git)
Create a notification for this product.
Linux Linux Affected: 6.19
Unaffected: 0 , < 6.19 (semver)
Unaffected: 7.0.12 , ≤ 7.0.* (semver)
Unaffected: 7.1 , ≤ * (original_commit_for_fix)
Create a notification for this product.
Show details on NVD website
To clipboard 

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "mm/vmalloc.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "ad7eff07b625f53c3fb513b30d7a8c5a79fbc7ce",
              "status": "affected",
              "version": "c6307674ed82c0c57d6e1e3408e84ac449ab8e94",
              "versionType": "git"
            },
            {
              "lessThan": "04aa71da5f35aacdc9ae9cb5150947daa624f641",
              "status": "affected",
              "version": "c6307674ed82c0c57d6e1e3408e84ac449ab8e94",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "mm/vmalloc.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.19"
            },
            {
              "lessThan": "6.19",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.0.*",
              "status": "unaffected",
              "version": "7.0.12",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.0.12",
                  "versionStartIncluding": "6.19",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1",
                  "versionStartIncluding": "6.19",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmm/vmalloc: do not trigger BUG() on BH disabled context\n\n__get_vm_area_node() currently triggers a BUG() if in_interrupt() returns\ntrue.  However, in_interrupt() also reports true when BH are disabled.\n\nThe bridge code can call rhashtable_lookup_insert_fast() with bottom\nhalves disabled:\n\n__vlan_add()\n -\u003e br_fdb_add_local()\n  spin_lock_bh(\u0026br-\u003ehash_lock); \u003c-- Disable BH\n   -\u003e fdb_add_local()\n    -\u003e fdb_create()\n     -\u003e rhashtable_lookup_insert_fast()\n      -\u003e kvmalloc()\n       -\u003e vmalloc()\n        -\u003e __get_vm_area_node()\n         -\u003e BUG_ON(in_interrupt())\n  spin_unlock_bh(\u0026br-\u003ehash_lock)\n\nthis triggers the BUG() despite the caller not being in NMI or\nhard IRQ context.\n\nReplace the in_interrupt() check with in_nmi() || in_hardirq()."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.5,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
            "version": "3.1"
          }
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-07-20T13:41:53.082Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/ad7eff07b625f53c3fb513b30d7a8c5a79fbc7ce"
        },
        {
          "url": "https://git.kernel.org/stable/c/04aa71da5f35aacdc9ae9cb5150947daa624f641"
        }
      ],
      "title": "mm/vmalloc: do not trigger BUG() on BH disabled context",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-63955",
    "datePublished": "2026-07-19T14:55:46.903Z",
    "dateReserved": "2026-07-19T07:54:57.023Z",
    "dateUpdated": "2026-07-20T13:41:53.082Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-63955",
      "date": "2026-07-21",
      "epss": "0.00467",
      "percentile": "0.37574"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-63955\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2026-07-19T16:17:14.307\",\"lastModified\":\"2026-07-20T15:16:59.057\",\"vulnStatus\":\"Received\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\nmm/vmalloc: do not trigger BUG() on BH disabled context\\n\\n__get_vm_area_node() currently triggers a BUG() if in_interrupt() returns\\ntrue.  However, in_interrupt() also reports true when BH are disabled.\\n\\nThe bridge code can call rhashtable_lookup_insert_fast() with bottom\\nhalves disabled:\\n\\n__vlan_add()\\n -\u003e br_fdb_add_local()\\n  spin_lock_bh(\u0026br-\u003ehash_lock); \u003c-- Disable BH\\n   -\u003e fdb_add_local()\\n    -\u003e fdb_create()\\n     -\u003e rhashtable_lookup_insert_fast()\\n      -\u003e kvmalloc()\\n       -\u003e vmalloc()\\n        -\u003e __get_vm_area_node()\\n         -\u003e BUG_ON(in_interrupt())\\n  spin_unlock_bh(\u0026br-\u003ehash_lock)\\n\\nthis triggers the BUG() despite the caller not being in NMI or\\nhard IRQ context.\\n\\nReplace the in_interrupt() check with in_nmi() || in_hardirq().\"}],\"affected\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"affectedData\":[{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"unaffected\",\"programFiles\":[\"mm/vmalloc.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"c6307674ed82c0c57d6e1e3408e84ac449ab8e94\",\"lessThan\":\"ad7eff07b625f53c3fb513b30d7a8c5a79fbc7ce\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"c6307674ed82c0c57d6e1e3408e84ac449ab8e94\",\"lessThan\":\"04aa71da5f35aacdc9ae9cb5150947daa624f641\",\"versionType\":\"git\",\"status\":\"affected\"}]},{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"affected\",\"programFiles\":[\"mm/vmalloc.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"6.19\",\"status\":\"affected\"},{\"version\":\"0\",\"lessThan\":\"6.19\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.0.12\",\"lessThanOrEqual\":\"7.0.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.1\",\"lessThanOrEqual\":\"*\",\"versionType\":\"original_commit_for_fix\",\"status\":\"unaffected\"}]}]}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H\",\"baseScore\":7.5,\"baseSeverity\":\"HIGH\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"NONE\",\"integrityImpact\":\"NONE\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":3.9,\"impactScore\":3.6}]},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/04aa71da5f35aacdc9ae9cb5150947daa624f641\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/ad7eff07b625f53c3fb513b30d7a8c5a79fbc7ce\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}",
    "redhat_vex": {
      "aggregate_severity": "Low",
      "current_release_date": "2026-07-21T16:17:33+00:00",
      "cve": "CVE-2026-63955",
      "id": "CVE-2026-63955",
      "initial_release_date": "2026-07-19T00:00:00+00:00",
      "product_status:known_affected": "14",
      "product_status:known_not_affected": "260",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: mm/vmalloc: do not trigger BUG() on BH disabled context",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-63955.json",
      "version": "3"
    }
  }
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.





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

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.