CVE-2026-97944 (GCVE-0-2026-97944)

Vulnerability from cvelistv5 – Published: 2026-09-25 10:22 – Updated: 2026-10-19 09:11
VLAI
Title
x86/cfi: Fix FineIBT hash offset in cfi_get_func_hash()
Summary
In the Linux kernel, the following vulnerability has been resolved: x86/cfi: Fix FineIBT hash offset in cfi_get_func_hash() The switch of the FineIBT preamble from "subl $hash, %r10d" to the shorter "subl $hash, %eax" moved the hash immediate from offset 7 to offset 5 of the preamble. fineibt_preamble_hash was updated to match, but the open-coded offset in cfi_get_func_hash() was missed and it still reads the hash at offset 7. cfi_get_func_hash() is used by the BPF JIT to give a struct_ops trampoline the CFI hash of the stub function it stands in for. With FineIBT the trampoline now gets the upper half of the real hash followed by the first two bytes of the next instruction, so the first indirect call from the kernel into a struct_ops program, tcp_init_congestion_control() calling ->init() of a BPF congestion control for example, fails the FineIBT check and the kernel dies with a CFI failure. Move the FineIBT preamble template and its offset defines above cfi_get_func_hash() and use fineibt_preamble_hash there, so every reader of the preamble shares one definition of its layout. The CFI_FINEIBT arm is only built with CONFIG_FINEIBT, the only configuration in which cfi_mode can take that value. cfi_get_func_arity() does not need the same treatment: the __bhi_args call whose displacement it reads still ends at the function address.
Severity
No CVSS data available.
Assigner
Linux CNA under the mitre root
CNA scorecard D 53/100 over 6642 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 85a2d4a890dce3cfc9c14aa91afc3dd7af8e3bf5 , < cd9b4595d6283f9b8a35d7ae607508de45a351ce (git)
Affected: 85a2d4a890dce3cfc9c14aa91afc3dd7af8e3bf5 , < 67cf94c30a8b5ebc839f282f5c5a522b35903524 (git)
Affected: 85a2d4a890dce3cfc9c14aa91afc3dd7af8e3bf5 , < 5a5d26f2cfe13467166219f6bf58099326912ddb (git)
guessed Create a notification for this product.
Linux Linux Affected: 6.18
Unaffected: 0 , < 6.18 (semver)
Unaffected: 6.18.53 , ≤ 6.18.* (semver)
Unaffected: 7.2.7 , ≤ 7.2.* (semver)
Unaffected: 7.3 , ≤ * (original_commit_for_fix)
guessed Create a notification for this product.
Show details on NVD website
To clipboard 

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "arch/x86/kernel/alternative.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "cd9b4595d6283f9b8a35d7ae607508de45a351ce",
              "status": "affected",
              "version": "85a2d4a890dce3cfc9c14aa91afc3dd7af8e3bf5",
              "versionType": "git"
            },
            {
              "lessThan": "67cf94c30a8b5ebc839f282f5c5a522b35903524",
              "status": "affected",
              "version": "85a2d4a890dce3cfc9c14aa91afc3dd7af8e3bf5",
              "versionType": "git"
            },
            {
              "lessThan": "5a5d26f2cfe13467166219f6bf58099326912ddb",
              "status": "affected",
              "version": "85a2d4a890dce3cfc9c14aa91afc3dd7af8e3bf5",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "arch/x86/kernel/alternative.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.18"
            },
            {
              "lessThan": "6.18",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.53",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.7",
              "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": "6.18.53",
                  "versionStartIncluding": "6.18",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2.7",
                  "versionStartIncluding": "6.18",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3",
                  "versionStartIncluding": "6.18",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nx86/cfi: Fix FineIBT hash offset in cfi_get_func_hash()\n\nThe switch of the FineIBT preamble from \"subl $hash, %r10d\" to the\nshorter \"subl $hash, %eax\" moved the hash immediate from offset 7 to\noffset 5 of the preamble. fineibt_preamble_hash was updated to match,\nbut the open-coded offset in cfi_get_func_hash() was missed and it\nstill reads the hash at offset 7.\n\ncfi_get_func_hash() is used by the BPF JIT to give a struct_ops\ntrampoline the CFI hash of the stub function it stands in for. With\nFineIBT the trampoline now gets the upper half of the real hash\nfollowed by the first two bytes of the next instruction, so the first\nindirect call from the kernel into a struct_ops program,\ntcp_init_congestion_control() calling -\u003einit() of a BPF congestion\ncontrol for example, fails the FineIBT check and the kernel dies with\na CFI failure.\n\nMove the FineIBT preamble template and its offset defines above\ncfi_get_func_hash() and use fineibt_preamble_hash there, so every\nreader of the preamble shares one definition of its layout. The\nCFI_FINEIBT arm is only built with CONFIG_FINEIBT, the only\nconfiguration in which cfi_mode can take that value.\ncfi_get_func_arity() does not need the same treatment: the __bhi_args\ncall whose displacement it reads still ends at the function address."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-19T09:11:10.690Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/cd9b4595d6283f9b8a35d7ae607508de45a351ce"
        },
        {
          "url": "https://git.kernel.org/stable/c/67cf94c30a8b5ebc839f282f5c5a522b35903524"
        },
        {
          "url": "https://git.kernel.org/stable/c/5a5d26f2cfe13467166219f6bf58099326912ddb"
        }
      ],
      "title": "x86/cfi: Fix FineIBT hash offset in cfi_get_func_hash()",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-97944",
    "datePublished": "2026-09-25T10:22:55.382Z",
    "dateReserved": "2026-09-25T10:18:58.204Z",
    "dateUpdated": "2026-10-19T09:11:10.690Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-97944",
      "date": "2026-11-10",
      "epss": "0.00166",
      "percentile": "0.05907"
    },
    "nvd": {
      "cve": {
        "affected": [
          {
            "affectedData": [
              {
                "defaultStatus": "unaffected",
                "product": "Linux",
                "programFiles": [
                  "arch/x86/kernel/alternative.c"
                ],
                "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                "vendor": "Linux",
                "versions": [
                  {
                    "lessThan": "cd9b4595d6283f9b8a35d7ae607508de45a351ce",
                    "status": "affected",
                    "version": "85a2d4a890dce3cfc9c14aa91afc3dd7af8e3bf5",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "67cf94c30a8b5ebc839f282f5c5a522b35903524",
                    "status": "affected",
                    "version": "85a2d4a890dce3cfc9c14aa91afc3dd7af8e3bf5",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "5a5d26f2cfe13467166219f6bf58099326912ddb",
                    "status": "affected",
                    "version": "85a2d4a890dce3cfc9c14aa91afc3dd7af8e3bf5",
                    "versionType": "git"
                  }
                ]
              },
              {
                "defaultStatus": "affected",
                "product": "Linux",
                "programFiles": [
                  "arch/x86/kernel/alternative.c"
                ],
                "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                "vendor": "Linux",
                "versions": [
                  {
                    "status": "affected",
                    "version": "6.18"
                  },
                  {
                    "lessThan": "6.18",
                    "status": "unaffected",
                    "version": "0",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "6.18.*",
                    "status": "unaffected",
                    "version": "6.18.53",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "7.2.*",
                    "status": "unaffected",
                    "version": "7.2.7",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "*",
                    "status": "unaffected",
                    "version": "7.3",
                    "versionType": "original_commit_for_fix"
                  }
                ]
              }
            ],
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
          }
        ],
        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nx86/cfi: Fix FineIBT hash offset in cfi_get_func_hash()\n\nThe switch of the FineIBT preamble from \"subl $hash, %r10d\" to the\nshorter \"subl $hash, %eax\" moved the hash immediate from offset 7 to\noffset 5 of the preamble. fineibt_preamble_hash was updated to match,\nbut the open-coded offset in cfi_get_func_hash() was missed and it\nstill reads the hash at offset 7.\n\ncfi_get_func_hash() is used by the BPF JIT to give a struct_ops\ntrampoline the CFI hash of the stub function it stands in for. With\nFineIBT the trampoline now gets the upper half of the real hash\nfollowed by the first two bytes of the next instruction, so the first\nindirect call from the kernel into a struct_ops program,\ntcp_init_congestion_control() calling -\u003einit() of a BPF congestion\ncontrol for example, fails the FineIBT check and the kernel dies with\na CFI failure.\n\nMove the FineIBT preamble template and its offset defines above\ncfi_get_func_hash() and use fineibt_preamble_hash there, so every\nreader of the preamble shares one definition of its layout. The\nCFI_FINEIBT arm is only built with CONFIG_FINEIBT, the only\nconfiguration in which cfi_mode can take that value.\ncfi_get_func_arity() does not need the same treatment: the __bhi_args\ncall whose displacement it reads still ends at the function address."
          }
        ],
        "id": "CVE-2026-97944",
        "lastModified": "2026-10-19T10:17:45.640",
        "metrics": {},
        "published": "2026-09-25T11:17:21.870",
        "references": [
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/5a5d26f2cfe13467166219f6bf58099326912ddb"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/67cf94c30a8b5ebc839f282f5c5a522b35903524"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/cd9b4595d6283f9b8a35d7ae607508de45a351ce"
          }
        ],
        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Received"
      }
    },
    "redhat_vex": {
      "aggregate_severity": "Low",
      "current_release_date": "2026-11-07T11:29:33+00:00",
      "cve": "CVE-2026-97944",
      "id": "CVE-2026-97944",
      "initial_release_date": "2026-09-25T00:00:00+00:00",
      "product_status:known_affected": "14",
      "product_status:known_not_affected": "189",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: x86/cfi: Fix FineIBT hash offset in cfi_get_func_hash()",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-97944.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "moderate",
      "current_release_date": "2026-11-11T01:08:38Z",
      "cve": "CVE-2026-97944",
      "id": "CVE-2026-97944",
      "initial_release_date": "2026-09-29T23:44:27Z",
      "product_status:known_affected": "16",
      "product_status:known_not_affected": "335",
      "product_status:recommended": "4",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-97944",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/2026/cve-2026-97944.json",
      "version": "5"
    }
  }
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.




Drag nodes to arrange them. Double-click a related vulnerability to open it, or a source to visit its link. The Physics button on the left tunes the layout and the simulation; the legend at the bottom left hides or shows nodes by kind and by sighting type.

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.
Vulnerability timeline

Sightings and recorded dates, grouped by day · UTC

JSON
How durations are calculated

Following the VTEM framework (Black Hat USA 2015), time to patch starts when the vendor or a coordinator was informed, total time to patch at discovery, and disclosure to patch at public disclosure; vendor response time runs from the report to its acknowledgement. Time to exploit and time unpatched start at the earliest discovery or report, falling back to public disclosure. Unpatched time ends at the first recorded patch, or the calculation time when no patch is recorded. Exploitation to patch shows the interval between those two events; a published proof of concept is a public exploit, not exploitation.

Each result shows its source dates. A negative interval means the end event came first; when date-only inputs leave the order open, the result says so. Date-only inputs are approximate. The earliest evidence wins: KEV report dates and sightings are labelled as such. Records describing another vulnerability are listed but never calculated from, and a PoC alone does not establish exploitation. Missing patch evidence does not prove that no patch exists. Filters below change the event list only.

Loading timeline…




    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.