NVD / CVE Program· CNA Linux

CVE-2026-43497: fbdev: udlfb: add vm_ops to dlfb_ops_mmap to prevent use-after-free

Noroxi assessment

Priority: Monitor (action score 29/100)

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: 0.11% (FIRST EPSS).
Someone with local access to the system can trigger it. A low-privileged account is enough. A user must open a link or visit a page. No special conditions are required; it is repeatable.
Fixed version: Linux Linux 18dd358de72d57993422cbb5dfb29ccd74efe192, 4f312c30f0368e8d2a76aa650dff73f23490b5e7, 5931f5651ee32bd41b3323256b31fcc8e71336ed; azl3 kernel 6.6.139.1-1 on Azure Linux 3.0 6.6.141.1-1.

Low priority for now. Upgrade to Linux Linux 18dd358de72d57993422cbb5dfb29ccd74efe192, 4f312c30f0368e8d2a76aa650dff73f23490b5e7, 5931f5651ee32bd41b3323256b31fcc8e71336ed; azl3 kernel 6.6.139.1-1 on Azure Linux 3.0 6.6.141.1-1 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: fbdev: udlfb: add vm_ops to dlfb_ops_mmap to prevent use-after-free dlfb_ops_mmap() uses remap_pfn_range() to map vmalloc framebuffer pages to userspace but sets no vm_ops on the VMA. This means the kernel cannot track active mmaps. When dlfb_realloc_framebuffer() replaces the backing buffer via FBIOPUT_VSCREENINFO, existing mmap PTEs are not invalidated. On USB disconnect, dlfb_ops_destroy() calls vfree() on the old pages while userspace PTEs still reference them, resulting in a use-after-free: the process retains read/write access to freed kernel pages. Add vm_operations_struct with open/close callbacks that maintain an atomic mmap_count on struct dlfb_data. In dlfb_realloc_framebuffer(), check mmap_count and return -EBUSY if the buffer is currently mapped, preventing buffer replacement while userspace holds stale PTEs. Tested with PoC using dummy_hcd + raw_gadget USB device emulation.

HighCVSS 7.3 · v3.1—No exploit Fix available

Memory safety

Published: May 21, 2026
Updated: Aug 5, 2026
EPSS: 0.1% · 1th percentile
CWE: CWE-416

Report tools

JSON

Action score

Monitor

Low priority for now.

CVSS: 29 / 40 · 7.3 / 10
CISA KEV: 0 / 30 · Not listed
EPSS: 0 / 30 · 0.1%

CNA vs NVD score

NVD: —
CNA · Linux: 7.3; 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.

Vendor	Product	CPE
linux	linux kernel	cpe:2.3:o:linux:linux_kernel

Affected versions

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

linux linux kernel4.19 and later · before 5.10.258
linux linux kernel5.11 and later · before 5.15.209
linux linux kernel5.16 and later · before 6.1.175
linux linux kernel6.2 and later · before 6.6.140
linux linux kernel6.7 and later · before 6.12.88
linux linux kernel6.13 and later · before 6.18.30
linux linux kernel6.19 and later · before 7.0.7
linux linux kernel7.1

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
- 4.19affected
- 7433914efd584b22bb49d3e1eee001f5d0525ecd and later · before 60f711cfd580f86fea8284146ac133804e728f9aaffected · git
- 7433914efd584b22bb49d3e1eee001f5d0525ecd and later · before 5931f5651ee32bd41b3323256b31fcc8e71336edaffected · git
- 7433914efd584b22bb49d3e1eee001f5d0525ecd and later · before e3d9865dacd7435b8465848428210d0f0c673311affected · git
- 7433914efd584b22bb49d3e1eee001f5d0525ecd and later · before 4f312c30f0368e8d2a76aa650dff73f23490b5e7affected · git
- 7433914efd584b22bb49d3e1eee001f5d0525ecd and later · before 18dd358de72d57993422cbb5dfb29ccd74efe192affected · git
- 7433914efd584b22bb49d3e1eee001f5d0525ecd and later · before da9b065cedfd3b574f229d5be594e6aa47a27ae6affected · git
- 7433914efd584b22bb49d3e1eee001f5d0525ecd and later · before a2c53a3822ee26e8d758071815b9ed3bf6669fc1affected · git
- 7433914efd584b22bb49d3e1eee001f5d0525ecd and later · before 8de779dc40d35d39fa07387b6f921eb11df0f511affected · git
- before 4.19not affected · semver

Package-level exposure

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

Ecosystem	Package	Affected range	Fix
Debian:12	linux	before 6.1.176-1	6.1.176-1
Debian:13	linux	before 6.12.88-1	6.12.88-1
Debian:14	linux	before 7.0.7-1	7.0.7-1
openSUSE:Tumbleweed	kernel-source	before 7.0.10-1.1	7.0.10-1.1

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-2026-43493May 19, 2026 · crypto: pcrypt - Fix handling of MAY_BACKLOG requests
39Monitor
← EarlierCVE-2026-43495May 21, 2026 · net: wwan: t7xx: validate port_count against message length in t7xx_port_enum_msg_handler
35Monitor
Later →CVE-2026-43498May 21, 2026 · accel/ivpu: Disallow re-exporting imported GEM objects
31Monitor

Remediation

Which version to upgrade to

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

Product / package	Fixed version	Source
Linux Linux	18dd358de72d57993422cbb5dfb29ccd74efe192	Vendor (CNA)
Linux Linux	4f312c30f0368e8d2a76aa650dff73f23490b5e7	Vendor (CNA)
Linux Linux	5931f5651ee32bd41b3323256b31fcc8e71336ed	Vendor (CNA)
Linux Linux	60f711cfd580f86fea8284146ac133804e728f9a	Vendor (CNA)
Linux Linux	8de779dc40d35d39fa07387b6f921eb11df0f511	Vendor (CNA)
Linux Linux	a2c53a3822ee26e8d758071815b9ed3bf6669fc1	Vendor (CNA)
Linux Linux	da9b065cedfd3b574f229d5be594e6aa47a27ae6	Vendor (CNA)
Linux Linux	e3d9865dacd7435b8465848428210d0f0c673311	Vendor (CNA)
azl3 kernel 6.6.139.1-1 on Azure Linux 3.0	6.6.141.1-1 · CBL-Mariner Releases	Microsoft (MSRC)
debian:linux	6.1.176-1 · Debian:12	Package registry (OSV)
opensuse:kernel-source	7.0.10-1.1 · openSUSE:Tumbleweed	Package 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.

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.
A user must open a link or visit a page.
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: Required
Scope: Unchanged
Confidentiality impact: High
Integrity impact: High
Availability impact: High

Weakness class (CWE)

CWE-416 · Use After Free

CVSS vector

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

nvd-secondary

Root cause

After a memory region is freed, another reference pointing to it is still used. By then, the same region may have been allocated for different data.

The bug in code

The whole CWE-416 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

1free(dev->buf);
2/* ... another thread is still running ... */
3process(dev->buf);

Fixed

1lock(&dev->lock);
2free(dev->buf);
3dev->buf = NULL;
4unlock(&dev->lock);

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

Fix✗ → ✓Sep 28, 2026, 10:09 PM UTC

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

References

git.kernel.org/stable/c/18dd358de72d57993422cbb5dfb29ccd74efe192

Show all references (7 more)

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

All records