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NVD / CVE Program· CNA Linux

CVE-2026-53402: fbdev: fbcon: fix out-of-bounds read in err_out of fbcon_do_set_font()

Noroxi assessment

Priority: Monitor (action score 28/100)

  • 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).
  • Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: Linux Linux 076b1aa65f77a49bce5a48a4a55a397cfcafa2b8, 3618a4c5b2591cfa83efe74f5b18c2d02b35c3f5, 39815715cbcfabb16fc8c5f4a23deeda20f5df62; azl3 kernel 6.6.144.1-1 on Azure Linux 3.0 6.6.145.2-1.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 076b1aa65f77a49bce5a48a4a55a397cfcafa2b8, 3618a4c5b2591cfa83efe74f5b18c2d02b35c3f5, 39815715cbcfabb16fc8c5f4a23deeda20f5df62; azl3 kernel 6.6.144.1-1 on Azure Linux 3.0 6.6.145.2-1 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: fbdev: fbcon: fix out-of-bounds read in err_out of fbcon_do_set_font() When fbcon_do_set_font() fails (e.g., due to a memory allocation failure inside vc_resize() under heavy memory pressure), it jumps to the `err_out` label to roll back the console state. However, the current rollback logic forgets to restore the `hi_font` state, leading to a severe state machine corruption. Earlier in the function, `set_vc_hi_font()` might be called to change `vc->vc_hi_font_mask` and mutate the screen buffer. If `vc_resize()` subsequently fails, the `err_out` path restores `vc_font.charcount` but entirely skips rolling back the `vc_hi_font_mask` and the screen buffer. This mismatch leaves the terminal in a desynchronized state. Because `vc_hi_font_mask` remains set, the VT subsystem will still accept character indices greater than 255 from userspace and write them to the screen buffer. Subsequent rendering calls (e.g., `fbcon_putcs()`) will then use these inflated indices to access the reverted, 256-character font array, leading to a deterministic out-of-bounds read and potential kernel memory disclosure. Fix this by adding the missing rollback logic for the `hi_font` mask and screen buffer in the error path.

HighCVSS 7.1 · v3.1—No exploit Fix available
Published
Jul 19, 2026
Updated
Oct 19, 2026
EPSS
0.1% · 6th percentile

Report tools

JSON

Action score

28

Monitor

Low priority for now.

CVSS
28 / 40 · 7.1 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · Linux
7.1
NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

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When you'll hear from us

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  • when exploit code appears or is weaponized
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  • when EPSS rises 20 points in a week

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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.

VendorProduct
linuxlinux kernel

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • linux linux kernel5.10.249 and later · before 5.10.261
  • linux linux kernel5.15.64 and later · before 5.15.212
  • linux linux kernel5.19.6 and later · before 6.0
  • linux linux kernel6.0.1 and later · before 6.1.178
  • linux linux kernel6.2 and later · before 6.6.145
  • linux linux kernel6.7 and later · before 6.12.96
  • linux linux kernel6.13 and later · before 6.18.39
  • linux linux kernel6.19 and later · before 7.1.3
  • linux linux kernel6.0

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

    • f08ccb792d3eaf1dc62d8cbf6a30d6522329f660, 6.0affected
    • 868749a7456dc48e93887a8474194e2ee6d6c21f and later · before cb016bcb40c81e7b19c4ae6143babb366dae8e20affected · git
    • ebd6f886aa2447fcfcdce5450c9e1028e1d681bb and later · before ac562193c36696513ae196171892e9338475c4bcaffected · git
    • a5a923038d70d2d4a86cb4e3f32625a5ee6e7e24 and later · before 3618a4c5b2591cfa83efe74f5b18c2d02b35c3f5affected · git
    • a5a923038d70d2d4a86cb4e3f32625a5ee6e7e24 and later · before a7a526fbc847f07ad3a503c7382189be5ab68574affected · git
    • a5a923038d70d2d4a86cb4e3f32625a5ee6e7e24 and later · before b5bb2c696e140c399cb874def2feedf61dee27d6affected · git
    • a5a923038d70d2d4a86cb4e3f32625a5ee6e7e24 and later · before 076b1aa65f77a49bce5a48a4a55a397cfcafa2b8affected · git
    • a5a923038d70d2d4a86cb4e3f32625a5ee6e7e24 and later · before 39815715cbcfabb16fc8c5f4a23deeda20f5df62affected · git
    • a5a923038d70d2d4a86cb4e3f32625a5ee6e7e24 and later · before 8fdc8c2057eea08d40ce2c8eed41ff9e451c65c2affected · git
    • 5.10.249 and later · before 5.10.261affected · semver

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.180-16.1.180-1
Debian:12linux-6.12before 6.12.100-1~deb12u16.12.100-1~deb12u1
Debian:13linuxbefore 6.12.96-16.12.96-1
Debian:14linuxbefore 7.1.3-17.1.3-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-31431crypto: algif_aead - Revert to operating out-of-placeKEV
    90Now
  • CVE-2022-0847A flaw was found in the way the "flags" member of the new pipe buffer structure was lacking proper initialization in copy_page_to_iter_pipe KEV
    89Now
  • CVE-2021-22555Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACEKEV
    85Now

Published before and after this one in the same product

  • ← EarlierCVE-2026-53400Jul 19, 2026 · i2c: core: fix adapter registration race
    31Monitor
  • ← EarlierCVE-2026-53401Jul 19, 2026 · fbdev: omap2: fix use-after-free in omapfb_mmap
    31Monitor
  • Later →CVE-2026-63795Jul 19, 2026 · 9p: avoid putting oldfid in p9_client_walk() error path
    40Plan

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 Linux076b1aa65f77a49bce5a48a4a55a397cfcafa2b8Vendor (CNA)
Linux Linux3618a4c5b2591cfa83efe74f5b18c2d02b35c3f5Vendor (CNA)
Linux Linux39815715cbcfabb16fc8c5f4a23deeda20f5df62Vendor (CNA)
Linux Linux5.10.261Vendor (CNA)
Linux Linux5.15.212Vendor (CNA)
Linux Linux5.20Vendor (CNA)
Linux Linux8fdc8c2057eea08d40ce2c8eed41ff9e451c65c2Vendor (CNA)
Linux Linuxa7a526fbc847f07ad3a503c7382189be5ab68574Vendor (CNA)
Linux Linuxac562193c36696513ae196171892e9338475c4bcVendor (CNA)
Linux Linuxb5bb2c696e140c399cb874def2feedf61dee27d6Vendor (CNA)
Linux Linuxcb016bcb40c81e7b19c4ae6143babb366dae8e20Vendor (CNA)
azl3 kernel 6.6.144.1-1 on Azure Linux 3.06.6.145.2-1 · CBL-Mariner ReleasesMicrosoft (MSRC)
debian:linux6.1.180-1 · Debian:12Package registry (OSV)
debian:linux-6.126.12.100-1~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.

No dated events beyond publication.

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).

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

All national notices →

Technical details

Attack conditions

  • Someone with local access to the system can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
high · data can be read
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
None
Availability impact
High

Weakness class (CWE)

CWE-125 · Out-of-bounds Read

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H

nvd-secondary

Attack context

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

ATT&CK techniques

—

Change log

  1. SSVC exploitation— → 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