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CVE.org (no NVD analysis yet)· CNA Linux

CVE-2026-98838: vt: skip screen update for DEC alignment test on backgroup consoles

Noroxi assessment

Priority: Monitor (action score 0/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.17% (FIRST EPSS).
  • Fixed version: Linux Linux 0928ed9bd7946baee911efa401088697836e3b1e, 0ee53081425a1a31ce15089012cd96b8353eb44e, 2fc4e71aefab57c80ccc9775aad2af503fc90810; azl3 kernel 6.6.157.1-1 on Azure Linux 3.0 Release Notes; azl3 kernel 6.6.159.1-1 on Azure Linux 3.0 6.6.161.1-1.

Low priority for now. Upgrade to Linux Linux 0928ed9bd7946baee911efa401088697836e3b1e, 0ee53081425a1a31ce15089012cd96b8353eb44e, 2fc4e71aefab57c80ccc9775aad2af503fc90810; azl3 kernel 6.6.157.1-1 on Azure Linux 3.0 Release Notes; azl3 kernel 6.6.159.1-1 on Azure Linux 3.0 6.6.161.1-1 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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(), ...).

—No exploit Fix available
Published
Oct 18, 2026
Updated
Oct 30, 2026
EPSS
0.1% · 7th percentile
CWE
—

Report tools

JSON

Action score

0

Monitor

Low priority for now.

CVSS
0 / 40 · —
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

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  • A fix has been released

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

—

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

  • Linux Linux

    • 2.6.12affected
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before d388658505bf707ff0cd7142c37c868febf8c2a5affected · git
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before 82561eee12a342994daf3a70590f5d07c35da743affected · git
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before 663cf98baced6941a0f3f00e1be61024e57d4429affected · git
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before 2fc4e71aefab57c80ccc9775aad2af503fc90810affected · git
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before 985c000b046ca4ee11ee34ef85db500c569ef6e8affected · git
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before ad06f7312d3f615dd466483ce81a9b9619166686affected · git
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before 0ee53081425a1a31ce15089012cd96b8353eb44eaffected · git
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before 0928ed9bd7946baee911efa401088697836e3b1eaffected · git
    • before 2.6.12not affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12linuxfrom 0—
Debian:12linux-6.12before 6.12.113-1~deb12u16.12.113-1~deb12u1
Debian:13linuxbefore 6.12.113-16.12.113-1
Debian:14linuxbefore 7.2.10-17.2.10-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-74705udp: fix potential use-after-free in tunnel segmentation
    40Plan
  • CVE-2026-74612veth: fix skb length accounting after XDP frag adjustment
    40Plan
  • CVE-2026-74475vxlan: use neigh_ha_snapshot() in route_shortcircuit()
    40Plan

Published before and after this one in the same product

  • ← EarlierCVE-2026-98836Oct 18, 2026 · ALSA: line6: reject oversized playback packets
    0Monitor
  • ← EarlierCVE-2026-98837Oct 18, 2026 · ALSA: caiaq: unregister the input device when probe fails
    0Monitor
  • Later →CVE-2026-98839Oct 18, 2026 · vt: selection: Fix unsigned underflow and slab-out-of-bounds read in paste_selection()
    0Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux0928ed9bd7946baee911efa401088697836e3b1eVendor (CNA)
Linux Linux0ee53081425a1a31ce15089012cd96b8353eb44eVendor (CNA)
Linux Linux2fc4e71aefab57c80ccc9775aad2af503fc90810Vendor (CNA)
Linux Linux663cf98baced6941a0f3f00e1be61024e57d4429Vendor (CNA)
Linux Linux82561eee12a342994daf3a70590f5d07c35da743Vendor (CNA)
Linux Linux985c000b046ca4ee11ee34ef85db500c569ef6e8Vendor (CNA)
Linux Linuxad06f7312d3f615dd466483ce81a9b9619166686Vendor (CNA)
Linux Linuxd388658505bf707ff0cd7142c37c868febf8c2a5Vendor (CNA)
azl3 kernel 6.6.157.1-1 on Azure Linux 3.0Release NotesMicrosoft (MSRC)
azl3 kernel 6.6.159.1-1 on Azure Linux 3.06.6.161.1-1 · Release NotesMicrosoft (MSRC)
debian:linux6.12.113-1 · Debian:13Package registry (OSV)
debian:linux-6.126.12.113-1~deb12u1 · Debian:12Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

  1. Published
  2. Fix recordedsame day
  3. TodayNov 9, 2026+22 d
EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

No CVSS vector for this record, so attack conditions can't be derived.

Weakness class (CWE)

—

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Exploit maturity— → none
  2. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (7 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records