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NVD / CVE Program· CNA Linux

CVE-2025-40304: fbdev: Add bounds checking in bit_putcs to fix vmalloc-out-of-bounds

Noroxi assessment

Priority: Monitor (action score 31/100)

  • 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: 0.14% (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 15ba9acafb0517f8359ca30002c189a68ddbb939, 1943b69e87b0ab35032d47de0a7fca9a3d1d6fc1, 2d1359e11674ed4274934eac8a71877ae5ae7bbb.

Low priority for now. Upgrade to Linux Linux 15ba9acafb0517f8359ca30002c189a68ddbb939, 1943b69e87b0ab35032d47de0a7fca9a3d1d6fc1, 2d1359e11674ed4274934eac8a71877ae5ae7bbb 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: Add bounds checking in bit_putcs to fix vmalloc-out-of-bounds Add bounds checking to prevent writes past framebuffer boundaries when rendering text near screen edges. Return early if the Y position is off-screen and clip image height to screen boundary. Break from the rendering loop if the X position is off-screen. When clipping image width to fit the screen, update the character count to match the clipped width to prevent buffer size mismatches. Without the character count update, bit_putcs_aligned and bit_putcs_unaligned receive mismatched parameters where the buffer is allocated for the clipped width but cnt reflects the original larger count, causing out-of-bounds writes.

HighCVSS 7.8 · v3.1—No exploit Fix available
Published
Dec 8, 2025
Updated
Oct 14, 2026
EPSS
0.1% · 3th percentile
CWE
—

Report tools

JSON

Action score

31

Monitor

Low priority for now.

CVSS
31 / 40 · 7.8 / 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
7.8
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.

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  • 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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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 996bfaa7372d6718b6d860bdf78f6618e850c702affected · git
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before f0982400648a3e00580253e0c48e991f34d2684caffected · git
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before 1943b69e87b0ab35032d47de0a7fca9a3d1d6fc1affected · git
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before ebc0730b490c7f27340b1222e01dd106e820320daffected · git
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before 86df8ade88d290725554cefd03101ecd0fbd3752affected · git
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before 15ba9acafb0517f8359ca30002c189a68ddbb939affected · git
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before 2d1359e11674ed4274934eac8a71877ae5ae7bbbaffected · git
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before 3637d34b35b287ab830e66048841ace404382b67affected · 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
AlmaLinux:10kernel-abi-stablelistsbefore 6.12.0-124.35.1.el10_16.12.0-124.35.1.el10_1
AlmaLinux:10kernel-docbefore 6.12.0-124.35.1.el10_16.12.0-124.35.1.el10_1
AlmaLinux:8bpftoolbefore 4.18.0-553.105.1.el8_104.18.0-553.105.1.el8_10
AlmaLinux:8kernelbefore 4.18.0-553.105.1.el8_104.18.0-553.105.1.el8_10
AlmaLinux:8kernel-abi-stablelistsbefore 4.18.0-553.105.1.el8_104.18.0-553.105.1.el8_10
AlmaLinux:8kernel-corebefore 4.18.0-553.105.1.el8_104.18.0-553.105.1.el8_10
AlmaLinux:8kernel-cross-headersbefore 4.18.0-553.105.1.el8_104.18.0-553.105.1.el8_10
AlmaLinux:8kernel-debugbefore 4.18.0-553.105.1.el8_104.18.0-553.105.1.el8_10
AlmaLinux:8kernel-debug-corebefore 4.18.0-553.105.1.el8_104.18.0-553.105.1.el8_10
AlmaLinux:8kernel-debug-develbefore 4.18.0-553.105.1.el8_104.18.0-553.105.1.el8_10
AlmaLinux:8kernel-debug-modulesbefore 4.18.0-553.105.1.el8_104.18.0-553.105.1.el8_10
AlmaLinux:8kernel-debug-modules-extrabefore 4.18.0-553.105.1.el8_104.18.0-553.105.1.el8_10
AlmaLinux:8kernel-develbefore 4.18.0-553.105.1.el8_104.18.0-553.105.1.el8_10
AlmaLinux:8kernel-docbefore 4.18.0-553.105.1.el8_104.18.0-553.105.1.el8_10
AlmaLinux:8kernel-headersbefore 4.18.0-553.105.1.el8_104.18.0-553.105.1.el8_10
AlmaLinux:8kernel-modulesbefore 4.18.0-553.105.1.el8_104.18.0-553.105.1.el8_10
AlmaLinux:8kernel-modules-extrabefore 4.18.0-553.105.1.el8_104.18.0-553.105.1.el8_10
AlmaLinux:8kernel-rtbefore 4.18.0-553.105.1.rt7.446.el8_104.18.0-553.105.1.rt7.446.el8_10
AlmaLinux:8kernel-rt-corebefore 4.18.0-553.105.1.rt7.446.el8_104.18.0-553.105.1.rt7.446.el8_10
AlmaLinux:8kernel-rt-debugbefore 4.18.0-553.105.1.rt7.446.el8_104.18.0-553.105.1.rt7.446.el8_10
AlmaLinux:8kernel-rt-debug-corebefore 4.18.0-553.105.1.rt7.446.el8_104.18.0-553.105.1.rt7.446.el8_10
AlmaLinux:8kernel-rt-debug-develbefore 4.18.0-553.105.1.rt7.446.el8_104.18.0-553.105.1.rt7.446.el8_10
AlmaLinux:8kernel-rt-debug-modulesbefore 4.18.0-553.105.1.rt7.446.el8_104.18.0-553.105.1.rt7.446.el8_10
AlmaLinux:8kernel-rt-debug-modules-extrabefore 4.18.0-553.105.1.rt7.446.el8_104.18.0-553.105.1.rt7.446.el8_10

+96

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-2025-40302Dec 8, 2025 · media: videobuf2: forbid remove_bufs when legacy fileio is active
    31Monitor
  • ← EarlierCVE-2025-40303Dec 8, 2025 · btrfs: ensure no dirty metadata is written back for an fs with errors
    31Monitor
  • Later →CVE-2025-40305Dec 8, 2025 · 9p/trans_fd: p9_fd_request: kick rx thread if EPOLLIN
    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 Linux15ba9acafb0517f8359ca30002c189a68ddbb939Vendor (CNA)
Linux Linux1943b69e87b0ab35032d47de0a7fca9a3d1d6fc1Vendor (CNA)
Linux Linux2d1359e11674ed4274934eac8a71877ae5ae7bbbVendor (CNA)
Linux Linux3637d34b35b287ab830e66048841ace404382b67Vendor (CNA)
Linux Linux86df8ade88d290725554cefd03101ecd0fbd3752Vendor (CNA)
Linux Linux996bfaa7372d6718b6d860bdf78f6618e850c702Vendor (CNA)
Linux Linuxebc0730b490c7f27340b1222e01dd106e820320dVendor (CNA)
Linux Linuxf0982400648a3e00580253e0c48e991f34d2684cVendor (CNA)
almalinux:bpftool4.18.0-553.105.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel4.18.0-553.105.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-abi-stablelists6.12.0-124.35.1.el10_1 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-core4.18.0-553.105.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-cross-headers4.18.0-553.105.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-debug4.18.0-553.105.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-debug-core4.18.0-553.105.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-debug-devel4.18.0-553.105.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-debug-modules4.18.0-553.105.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-debug-modules-extra4.18.0-553.105.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-devel4.18.0-553.105.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-doc6.12.0-124.35.1.el10_1 · AlmaLinux:10Package registry (OSV)
debian:linux6.1.159-1 · Debian:12Package registry (OSV)
red hat:kernel-64k-debug-debuginfo0:6.12.0-55.58.1.el10_0 · Red Hat:enterprise_linux_eus:10.0Package registry (OSV)
red hat:kernel-64k-debug-devel0:6.12.0-55.58.1.el10_0 · Red Hat:enterprise_linux_eus:10.0Package registry (OSV)
red hat:kernel-64k-debug-devel-matched0:6.12.0-55.58.1.el10_0 · Red Hat:enterprise_linux_eus:10.0Package registry (OSV)
red hat:kernel-64k-debuginfo0:6.12.0-55.58.1.el10_0 · Red Hat:enterprise_linux_eus:10.0Package registry (OSV)
red hat:kernel-64k-devel0:6.12.0-55.58.1.el10_0 · Red Hat:enterprise_linux_eus:10.0Package registry (OSV)
red hat:kernel-64k-devel-matched0:6.12.0-55.58.1.el10_0 · Red Hat:enterprise_linux_eus:10.0Package registry (OSV)
red hat:kernel-debug-debuginfo0:6.12.0-55.58.1.el10_0 · Red Hat:enterprise_linux_eus:10.0Package registry (OSV)
red hat:kernel-debug-devel0:6.12.0-55.58.1.el10_0 · Red Hat:enterprise_linux_eus:10.0Package registry (OSV)
red hat:kernel-debug-devel-matched0:6.12.0-55.58.1.el10_0 · Red Hat:enterprise_linux_eus:10.0Package registry (OSV)

+5

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.

No history yet (it accumulates with the daily EPSS job).

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

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
high · data or configuration can be modified
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
High
Availability impact
High

Weakness class (CWE)

—

CVSS vector

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

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

Change log

  1. 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