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CVE-2026-98838

vt: skip screen update for DEC alignment test on backgroup consoles

Products / packages Linux

Published

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Severity and exploitation

Not in CISA KEVNo CVSS score

KEV coverage does not rule out exploitation.

KEV checked 14/11/2026, 22:55:31 UTC

Severity

unknown

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

The Linux kernel has a vulnerability where the vt skips screen updates for DEC alignment tests on background consoles, potentially causing an out-of-bounds access. This issue affects Linux kernel versions prior to 5.10.273, 5.15.224, 6.1.191, 6.6.160, 6.12.113, 6.18.56, and 7.2.10. The vulnerability requires local access to exploit.

Summarized by @cf/meta/llama-3.3-70b-instruct-fp8-fast. Verify details against the original sources.

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

8 ranges
Linux version evidence

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

affected

1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 → before d388658505bf707ff0cd7142c37c868febf8c2a5

git versions

1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 → before 82561eee12a342994daf3a70590f5d07c35da743

git versions

1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 → before 663cf98baced6941a0f3f00e1be61024e57d4429

git versions

1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 → before 2fc4e71aefab57c80ccc9775aad2af503fc90810

git versions

1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 → before 985c000b046ca4ee11ee34ef85db500c569ef6e8

git versions

1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 → before ad06f7312d3f615dd466483ce81a9b9619166686

git versions

1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 → before 0ee53081425a1a31ce15089012cd96b8353eb44e

git versions

1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 → before 0928ed9bd7946baee911efa401088697836e3b1e

git versions

unaffected

unknown

Other versions: unaffected

Linux · Linux

Linux

10 ranges
Linux version evidence

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

affected

2.6.12

unaffected

0 → before 2.6.12

semver versions

5.10.273 → through 5.10.*

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

6.12.113 → through 6.12.*

semver versions

6.18.56 → through 6.18.*

semver versions

7.2.10 → 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:

vt: skip screen update for DEC alignment test on backgroup consoles

[BUG] Recently, we encountered a KASAN warning as follows:

BUG: KASAN: slab-out-of-bounds in fb_pad_aligned_buffer+0x11f/0x140 Read of size 1 at addr ff1100015fd9f6a4 by task tty_fbcon_oob/1239 CPU: 7 UID: 0 PID: 1239 Comm: tty_fbcon_oob Not tainted 7.3.0-rc1 #100 PREEMPT(full) Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.17.0-4.fc41 04/01/2014 Call Trace: <TASK> ... kasan_report+0xf0/0x120 fb_pad_aligned_buffer+0x11f/0x140 ccw_putcs+0x86c/0xa80 fbcon_putcs+0x338/0x410 do_update_region+0x21d/0x450 do_con_write+0x1e0e/0x4880 con_write+0x13/0x80 n_tty_write+0x374/0x1010 file_tty_write.isra.0+0x404/0x7a0 ...

reproduce:

  1. open /dev/tty0, set a KDFONTOP ioctl with op.op = KD_FONT_OP_SET, op.width = 8 and op.height = 16 (visible VC1)
  2. open /dev/tty1, set a KDFONTOP ioctl with op.op = KD_FONT_OP_SET, op.width = 28 and op.height = 24 (invisible VC2)
  3. echo 3 > /sys/devices/virtual/graphics/fbcon/rotate_all
  4. write EShash8(esc hash8) to tty1

[CAUSE] All VCs render to the framebuffer. setfont only modifies the target VC's font without resizing the framebuffer backing buffer (par->rotated.buf); the buffer is only resized for the visible VC (fbcon_do_set_font -> ... -> vc_do_resize -> update_screen). This relies on the con_should_update() check performed before every update_region().

However, the ESC # 8 path (do_con_trol -> do_update_region) omits the con_should_update() check. After changing the font size of an invisible VC, do_update_region() fills using the new font size against a buffer that was never resized, causing an out-of-bounds access.

[FIX] Only push the update when the console is visible and not blanked, add the con_should_update() check in the do_con_trol() like every other call site of do_update_region() (update_region(), invert_screen(), ...).

References

8 sources
git.kernel.org/stable/c/d388658505bf707ff0cd7142c37c868febf8c2a5
Source referenceLinux
git.kernel.org/stable/c/82561eee12a342994daf3a70590f5d07c35da743
Source referenceLinux
git.kernel.org/stable/c/663cf98baced6941a0f3f00e1be61024e57d4429
Source referenceLinux
git.kernel.org/stable/c/2fc4e71aefab57c80ccc9775aad2af503fc90810
Source referenceLinux
git.kernel.org/stable/c/985c000b046ca4ee11ee34ef85db500c569ef6e8
Source referenceLinux
git.kernel.org/stable/c/ad06f7312d3f615dd466483ce81a9b9619166686
Source referenceLinux
View 2 more references
git.kernel.org/stable/c/0ee53081425a1a31ce15089012cd96b8353eb44e
Source referenceLinux
git.kernel.org/stable/c/0928ed9bd7946baee911efa401088697836e3b1e
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-2026-98838

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): 2.6.12

Before: 5.10.273

Vulnerable product

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

From (inclusive): 2.6.12

Before: 5.15.224

Vulnerable product

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

From (inclusive): 2.6.12

Before: 6.1.191

Vulnerable product

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

From (inclusive): 2.6.12

Before: 6.6.160

Vulnerable product

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

From (inclusive): 2.6.12

Before: 6.12.113

Vulnerable product

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

From (inclusive): 2.6.12

Before: 6.18.56

Vulnerable product

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

From (inclusive): 2.6.12

Before: 7.2.10

Vulnerable product

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

From (inclusive): 2.6.12

Before: 7.3

Applicability preview
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  {
    "nodes": [
      {
        "operator": "OR",
        "negate": false,
        "cpeMatch": [
          {
            "vulnerable": true,
            "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
            "versionStartIncluding": "2.6.12",
            "versionEndExcluding": "5.10.273"
          },
          {
            "vulnerable": true,
            "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
            "versionStartIncluding": "2.6.12",
            "versionEndExcluding": "5.15.224"
          },
          {
            "vulnerable": true,
            "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
            "versionStartIncluding": "2.6.12",
            "versionEndExcluding": "6.1.191"
          },
          {
            "vulnerable": true,
            "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
            "versionStartIncluding": "2.6.12",
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          {
            "vulnerable": true,
            "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
            "versionStartIncluding": "2.6.12",
            "versionEndExcluding": "6.12.113"
          },
          {
            "vulnerable": true,
            "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
            "versionStartIncluding": "2.6.12",
            "versionEndExcluding": "6.18.56"
          },
          {
            "vulnerable": true,
            "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
            "versionStartIncluding": "2.6.12",
            "versionEndExcluding": "7.2.10"
          },
          {
            "vulnerable": true,
            "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
            "versionStartIncluding": "2.6.12",
            "versionEndExcluding": "7.3"
          }
        ]
      }
    ]
  }
]
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.