CVE-2026-99274

Description

In the Linux kernel, the following vulnerability has been resolved: smb: client: fix fiemap wild read on empty truncated response smb3_fiemap() treats -E2BIG from SMB2_ioctl() as a truncated range blob and loops for the next chunk. If the server reports STATUS_BUFFER_OVERFLOW with OutputCount == 0, SMB2_ioctl() returns -E2BIG with out_data == NULL and out_data_len == 0, and the existing length checks accept the empty result. The loop then evaluates next = out_data[num - 1].file_offset + ... with num == 0, reading 16 bytes before NULL. Reject a truncated range blob that contains no range, so the resume offset is never computed from an empty response. Also require the last range in a truncated blob to advance the resume offset without overflowing, and to stay within the requested range; a malicious or broken server could otherwise make no progress or underflow len and loop forever. Free the previous response buffer before retrying. Reproduced on 6.6.87.2 with a malicious SMB2 server that answers FSCTL_QUERY_ALLOCATED_RANGES with STATUS_BUFFER_OVERFLOW and OutputCount == 0; an FS_IOC_FIEMAP ioctl on the mount oopses in cifs_fiemap() with CR2 = fffffffffffffff8. The code path is unchanged on mainline.

Overview

State: PUBLISHED
Assigner (CNA): Linux
CVSS severity: —
CVSS score: —
CVSS vector: —
Effective score: no score available from CNA, NVD, or AI yet
CWE(s): —
Reserved: 2026-09-25
Published: 2026-11-07 14:08 UTC
Last updated: 2026-11-07 14:08 UTC
Source: https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/99xxx/CVE-2026-99274.json

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European Union Vulnerability Database ENISA EUVD

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EUVD ID: EUVD-2026-119288

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Affected products (2)

Vendor	Product	Versions	Platforms
Linux	Linux	`2f3ebaba13cebd8badfb9aed31c0cf3cc82eb4f4` (affected), `2f3ebaba13cebd8badfb9aed31c0cf3cc82eb4f4` (affected), `2f3ebaba13cebd8badfb9aed31c0cf3cc82eb4f4` (affected)	—
Linux	Linux	`5.2` (affected), `0` (unaffected), `6.18.61` (unaffected), `7.3.2` (unaffected), `7.4-rc1` (unaffected)	—

Vendor references (3)

References embedded in the original CVE record by the assigning CNA.

Web references (0)

DuckDuckGo results ranked by threat-intel / vendor advisory domains. Generated by the 🔎 Find references (web) button above — same flow as the Remediations search.

No web references attached yet.

Remediations (10)

CVE-2026-99274 - Red Hat Customer Portal

web:access.redhat.com

A deferred status means that a fix for an affected product version is not guaranteed due to higher-priority development work. Available options depend mostly on the Impact of the vulnerability and the current Life Cycle phase of your product. Overall, you have the following options: Apply a mitigation (if one exists).

2026-11-08 11:08 UTC
Security Updates - Red Hat Customer Portal

web:access.redhat.com

Products & tools Red Hat Documentation Find answers, get guidance, and learn how to use Red Hat products. Red Hat Ecosystem Catalog Find hardware, software, and cloud providers―and download container images―certified to perform with Red Hat technologies.

2026-11-08 11:08 UTC
October 2026 Critical Patch Update Released | security

web:blogs.oracle.com

For more information about the Critical Patch Update program, see the security vulnerability remediation practices page located on the Oracle Trust Center.

2026-11-08 11:08 UTC
CVE Database Search & Remediation Guidance

web:cvedatabase.com

Search and analyze CVE vulnerabilities with instant access to CVSS scores, affected products, and remediation guidance.

2026-11-08 11:08 UTC
CVE Vulnerabilities 2026: Critical Flaws & Fixes Hub

web:cyberupdates365.com

Track critical CVE vulnerabilities 2026 with verified enterprise patch guides. Fix zero-days across VMware, WordPress, Windows, and cloud infrastructure.

2026-11-08 11:08 UTC
SAP Security Patch Day - October 2026

web:support.sap.com

On 13 th of October 2026 , SAP security patch day saw the release of 16 new security notes and 4 GitHub security advisories. There are 2 updates to previously released security notes.

2026-11-08 11:08 UTC
CVE-2026-99274 - Linux Kernel smb:client Vulnerability…

web:vulmon.com

Linux Kernel smb:client Vulnerability Allows Kernel Crash via Malicious SMB2 Server. A vulnerability in the Linux kernel's smb:client component may lead to a…

2026-11-08 11:08 UTC
Oracle Critical Patch Update Advisory - July 2026

web:www.oracle.com

This Critical Patch Update contains 1448 new security patches across the product families listed below. Please note that a My Oracle Support (MOS) note summarizing the content of this Critical Patch Update and other Oracle Software Security Assurance activities is located at July 2026 Critical Patch Update: Executive Summary and Analysis.

2026-11-08 11:08 UTC
Oracle Critical Security Patch Update Advisory - September 2026

web:www.oracle.com

Prior Critical Patch Update and Critical Security Patch Update advisories should be reviewed for information regarding earlier published security patches. Refer to Critical Patch Updates, Critical Security Patch Updates, Security Alerts and Bulletins for information about Oracle Security advisories.

2026-11-08 11:08 UTC
The CVE Database: Curated Vulnerability Intelligence by Wiz | Wiz

web:www.wiz.io

Wiz's CVE Database curates CVE data to create easy-to-navigate profiles that cover the entire vulnerability timeline, exploit scenarios, and mitigation steps.

2026-11-08 11:08 UTC

AI Forensic Analysis

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Raw JSON

The full cvelistV5 record. Download as CVE-2026-99274.json.

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/smb/client/smb2ops.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "4a426ca5be7e3dedbe76575b967db04fbf01136f",
              "status": "affected",
              "version": "2f3ebaba13cebd8badfb9aed31c0cf3cc82eb4f4",
              "versionType": "git"
            },
            {
              "lessThan": "31f6dbb29fe17fa9595c7e8b19fd92915b03a4ca",
              "status": "affected",
              "version": "2f3ebaba13cebd8badfb9aed31c0cf3cc82eb4f4",
              "versionType": "git"
            },
            {
              "lessThan": "f5baa17a0f316c235d61623ac8e8fb32c2b3c0cc",
              "status": "affected",
              "version": "2f3ebaba13cebd8badfb9aed31c0cf3cc82eb4f4",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/smb/client/smb2ops.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.2"
            },
            {
              "lessThan": "5.2",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.61",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.3.*",
              "status": "unaffected",
              "version": "7.3.2",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.4-rc1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.61",
                  "versionStartIncluding": "5.2",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3.2",
                  "versionStartIncluding": "5.2",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.4-rc1",
                  "versionStartIncluding": "5.2",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: fix fiemap wild read on empty truncated response\n\nsmb3_fiemap() treats -E2BIG from SMB2_ioctl() as a truncated range blob\nand loops for the next chunk. If the server reports\nSTATUS_BUFFER_OVERFLOW with OutputCount == 0, SMB2_ioctl() returns\n-E2BIG with out_data == NULL and out_data_len == 0, and the existing\nlength checks accept the empty result. The loop then evaluates\n\n\tnext = out_data[num - 1].file_offset + ...\n\nwith num == 0, reading 16 bytes before NULL.\n\nReject a truncated range blob that contains no range, so the resume\noffset is never computed from an empty response. Also require the last\nrange in a truncated blob to advance the resume offset without\noverflowing, and to stay within the requested range; a malicious or\nbroken server could otherwise make no progress or underflow len and loop\nforever. Free the previous response buffer before retrying.\n\nReproduced on 6.6.87.2 with a malicious SMB2 server that answers\nFSCTL_QUERY_ALLOCATED_RANGES with STATUS_BUFFER_OVERFLOW and\nOutputCount == 0; an FS_IOC_FIEMAP ioctl on the mount oopses in\ncifs_fiemap() with CR2 = fffffffffffffff8. The code path is unchanged\non mainline."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-11-07T14:08:45.924Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/4a426ca5be7e3dedbe76575b967db04fbf01136f"
        },
        {
          "url": "https://git.kernel.org/stable/c/31f6dbb29fe17fa9595c7e8b19fd92915b03a4ca"
        },
        {
          "url": "https://git.kernel.org/stable/c/f5baa17a0f316c235d61623ac8e8fb32c2b3c0cc"
        }
      ],
      "title": "smb: client: fix fiemap wild read on empty truncated response",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-99274",
    "datePublished": "2026-11-07T14:08:45.924Z",
    "dateReserved": "2026-09-25T10:25:14.405Z",
    "dateUpdated": "2026-11-07T14:08:45.924Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}