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CVE-2026-99083

ksmbd: fix heap out-of-bounds write in krb5_authenticate()

Products / packages Linux

Published

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Severity and exploitation

Not in CISA KEV

KEV coverage does not rule out exploitation.

KEV checked 14/11/2026, 21:30:34 UTC
Linux · CVSS:3.1 · 8.8
Assessment vectorCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Severity

high8.8

CVSS measures technical severity, not the likelihood of an attack.

Known exploitation

Not listed in the checked CISA KEV catalog

Absence from CISA KEV does not rule out attacks.

Public exploit

Not established by this record

Missing evidence does not mean no public exploit exists.

Remediation

Fix status not established

No structured fix or guidance is available here. Check the latest publisher advisory.

What this means

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

Source excerpt · Linux

Attack conditions

No attack-condition excerpt has been identified here. Review the full source description and references for authentication, network access, and configuration requirements.

Review supporting sources →

Affected versions

Check the exact model, release, and any platform requirements against your installation.

Linux · Linux

Linux

11 ranges
Linux version evidence

Compare with this publisher’s ranges. This does not inspect your installation.

affected

676392184785ace61e939831e7ca44a03d438c3b → before a07dfb33112a42437f9d2d0bfd35c68575257381

git versions

ef572ffa8eb44111eed2925fbb2adca78bdcbf61 → before 1f73a6d40f4d1bae4f3491c0ec1ea8ee6ce035ff

git versions

98422bdd4cb3ca4d08844046f6507d7ec2c2b8d8 → before 59c6dcc5dd9dafe764ca0d40525933b2be69b059

git versions

98422bdd4cb3ca4d08844046f6507d7ec2c2b8d8 → before 80af1bde97d5a85ad6f2c40ca894ccc8fa75a27a

git versions

98422bdd4cb3ca4d08844046f6507d7ec2c2b8d8 → before 517404e157395d0f8da125ca956c566895dfcd06

git versions

98422bdd4cb3ca4d08844046f6507d7ec2c2b8d8 → before 4722d06b2907585074252061b1024a696c1cfc23

git versions

98422bdd4cb3ca4d08844046f6507d7ec2c2b8d8 → before 23a0be6a84a38ac169eeab49017934e8e27c65f0

git versions

2ba03cecb12ac7ac9e0170e251543c56832d9959

git versions

5.15.145 → before 5.15.224

semver versions

6.1.40 → before 6.1.191

semver versions

6.4.5 → before 6.5

semver versions

unaffected

unknown

Other versions: unaffected

Linux · Linux

Linux

9 ranges
Linux version evidence

Compare with this publisher’s ranges. This does not inspect your installation.

affected

6.5

unaffected

0 → before 6.5

semver versions

5.15.224 → through 5.15.*

semver versions

6.1.191 → through 6.1.*

semver versions

6.6.160 → through 6.6.*

semver versions

6.12.114 → through 6.12.*

semver versions

6.18.58 → through 6.18.*

semver versions

7.2.12 → through 7.2.*

semver versions

7.3 → through *

original_commit_for_fix versions

unknown

Other versions: affected

Automatic dependency matching is unavailable for this record. Use the product evidence and publisher’s instructions to check your installation.

What to do

Compare your installed product and version with the affected versions above. A matching product name alone does not confirm exposure.

No structured fix or remediation guidance is available here. Check the full source description and vendor’s latest advisory for a patch or workaround; do not assume another version is safe.

cve.new guidance unless attributed to a publisher. This page does not inspect your installation.

Public exploit evidence

No public exploit reference is identified in the imported evidence. This is not a claim that no exploit exists.

Original source description

Read the full publisher description

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

ksmbd: fix heap out-of-bounds write in krb5_authenticate()

In krb5_authenticate(), out_len is calculated to determine available headroom in response_buf for the incoming Kerberos AP-REP token. However, when SMB2_SESSION_SETUP is processed as a non-first element of a compounded SMB2 request, the calculation omits work->next_smb2_rsp_hdr_off.

This causes out_len to overstate remaining buffer headroom by the cumulative size of prior responses in the compound chain. Consequently, the length check in ksmbd_krb5_authenticate() (*out_len <= resp->spnego_blob_len) passes erroneously, allowing memcpy() to write the AP-REP blob past the end of response_buf into adjacent kernel heap memory.

Fix this by subtracting work->next_smb2_rsp_hdr_off when computing out_len, ensuring it accurately reflects physical remaining buffer space.

References

7 sources
git.kernel.org/stable/c/a07dfb33112a42437f9d2d0bfd35c68575257381
Source referenceLinux
git.kernel.org/stable/c/1f73a6d40f4d1bae4f3491c0ec1ea8ee6ce035ff
Source referenceLinux
git.kernel.org/stable/c/59c6dcc5dd9dafe764ca0d40525933b2be69b059
Source referenceLinux
git.kernel.org/stable/c/80af1bde97d5a85ad6f2c40ca894ccc8fa75a27a
Source referenceLinux
git.kernel.org/stable/c/517404e157395d0f8da125ca956c566895dfcd06
Source referenceLinux
git.kernel.org/stable/c/4722d06b2907585074252061b1024a696c1cfc23
Source referenceLinux
View 1 more references
git.kernel.org/stable/c/23a0be6a84a38ac169eeab49017934e8e27c65f0
Source referenceLinux

Inside the record

Evidence available

Package identity · not supplied
Version evidence
Remediation guidance · not supplied
Weakness classification · not supplied
Additional publishers · not supplied

Describes the evidence in this view, not whether the product is safe.

Original records

CVE-2026-99083

View the latest unmodified CVE JSON from the official source. It may be newer than this imported page.

cve.new JSON →

Environment requirements

These conditions apply together as specified by the publisher. A matching product name alone does not establish exposure.

Linux · platform conditions

Any condition may hold

Vulnerable product

cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*

From (inclusive): 5.15.145

Before: 5.15.224

Vulnerable product

cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*

From (inclusive): 6.1.40

Before: 6.1.191

Vulnerable product

cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*

From (inclusive): 6.5

Before: 6.6.160

Vulnerable product

cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*

From (inclusive): 6.5

Before: 6.12.114

Vulnerable product

cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*

From (inclusive): 6.5

Before: 6.18.58

Vulnerable product

cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*

From (inclusive): 6.5

Before: 7.2.12

Vulnerable product

cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*

From (inclusive): 6.5

Before: 7.3

Vulnerable product

cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*

From (inclusive): 6.4.5

Applicability preview
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  {
    "nodes": [
      {
        "operator": "OR",
        "negate": false,
        "cpeMatch": [
          {
            "vulnerable": true,
            "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
            "versionStartIncluding": "5.15.145",
            "versionEndExcluding": "5.15.224"
          },
          {
            "vulnerable": true,
            "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
            "versionStartIncluding": "6.1.40",
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          {
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            "versionStartIncluding": "6.5",
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          {
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          {
            "vulnerable": true,
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            "versionStartIncluding": "6.5",
            "versionEndExcluding": "6.18.58"
          },
          {
            "vulnerable": true,
            "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
            "versionStartIncluding": "6.5",
            "versionEndExcluding": "7.2.12"
          },
          {
            "vulnerable": true,
            "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
            "versionStartIncluding": "6.5",
            "versionEndExcluding": "7.3"
          },
          {
            "vulnerable": true,
            "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
            "versionStartIncluding": "6.4.5"
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    ]
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]
Contributing organizations · 1
Linux

Assigning organization

2026-10-30

Timeline

All times UTC

  1. Advisory published

    Publication date supplied by the source.

  2. Source updated

    Latest modification date supplied by the source.

  3. Last imported by cve.new

    Latest catalog import, not the date we first saw this advisory.

What changed

Follow changes
No substantive changes have been recorded here yet. History starts when cve.new observes a change after tracking is enabled; earlier edits are not reconstructed.

Large field values are marked as truncated previews. Original source snapshots remain retained.