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NVD / CVE Program· CNA Linux

CVE-2026-63856: drm/amdgpu/vcn: set no_user_fence for VCN v2.0 enc/dec rings

HighCVSS 7.8 · v3.1—No exploit Fix available

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: 0.17% (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 5e777bc4cbe928ac0fd95e368fee1540f2ce4db2, 8d80b293b41fcb5e9396db93e788b0f4ebcbafb7, ac06ce5cac9e711281585d09d00c6efcd9b86396.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 5e777bc4cbe928ac0fd95e368fee1540f2ce4db2, 8d80b293b41fcb5e9396db93e788b0f4ebcbafb7, ac06ce5cac9e711281585d09d00c6efcd9b86396 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: drm/amdgpu/vcn: set no_user_fence for VCN v2.0 enc/dec rings VCN encoder and decoder rings do not support 64-bit user fence writes, reject CS submissions with user fences. (cherry picked from commit e2b5499fca55f1a32960a311bbb62e35891eaf73)

Published
Jul 19, 2026
Updated
Oct 30, 2026
EPSS
0.1% · 7th percentile

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
total

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.

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

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2026-63856

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • 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

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

    • 5.3affected
    • 1b61de45dfaff00b627e47349a019658e39268b9 and later · before bcb972496f189edbf56a18b14f9b4831fd127ab8affected · git
    • 1b61de45dfaff00b627e47349a019658e39268b9 and later · before f264019be80de79f84f464846451445923bffea0affected · git
    • 1b61de45dfaff00b627e47349a019658e39268b9 and later · before 5e777bc4cbe928ac0fd95e368fee1540f2ce4db2affected · git
    • 1b61de45dfaff00b627e47349a019658e39268b9 and later · before ac06ce5cac9e711281585d09d00c6efcd9b86396affected · git
    • 1b61de45dfaff00b627e47349a019658e39268b9 and later · before c71aecae98e42dcf2baf462df50b3a2cf1a93fe4affected · git
    • 1b61de45dfaff00b627e47349a019658e39268b9 and later · before 8d80b293b41fcb5e9396db93e788b0f4ebcbafb7affected · git
    • before 5.3not affected · semver
    • 6.1.191 and later · up to and including 6.1.*not affected · semver
    • 6.6.141 and later · up to and including 6.6.*not affected · semver
Affected versions · NVD (5)

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

  • linux linux kernel5.3 and later · before 6.6.141
  • linux linux kernel6.7 and later · before 6.12.91
  • linux linux kernel6.13 and later · before 6.18.33
  • linux linux kernel6.19 and later · before 7.0.10
  • linux linux kernel7.1

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12linuxfrom 0—
Debian:13linuxbefore 6.12.94-16.12.94-1
Debian:14linuxbefore 7.0.10-17.0.10-1

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-2026-63854Jul 19, 2026 · drm/amdgpu/vcn: set no_user_fence for VCN v3.0 enc/dec rings
    31Monitor
  • ← EarlierCVE-2026-63855Jul 19, 2026 · drm/amdgpu/vcn: set no_user_fence for VCN v2.5 enc/dec rings
    31Monitor
  • Later →CVE-2026-63857Jul 19, 2026 · net: airoha: Do not read uninitialized fragment address in airoha_dev_xmit()
    39Monitor

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 Linux5e777bc4cbe928ac0fd95e368fee1540f2ce4db2Vendor (CNA)
Linux Linux8d80b293b41fcb5e9396db93e788b0f4ebcbafb7Vendor (CNA)
Linux Linuxac06ce5cac9e711281585d09d00c6efcd9b86396Vendor (CNA)
Linux Linuxbcb972496f189edbf56a18b14f9b4831fd127ab8Vendor (CNA)
Linux Linuxc71aecae98e42dcf2baf462df50b3a2cf1a93fe4Vendor (CNA)
Linux Linuxf264019be80de79f84f464846451445923bffea0Vendor (CNA)
debian:linux6.12.94-1 · Debian:13Package 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).

Variant candidates

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

  • CVE-2026-640370 days apartwifi: iwlwifi: mld: fix TSO segmentation explosion when AMSDU is disabled
    39Monitor
  • CVE-2026-640460 days apartnet: tls: prevent chain-after-chain in plain text SG
    39Monitor
  • CVE-2026-5322124 days apartip6_vti: fix incorrect tunnel matching in vti6_tnl_lookup()
    39Monitor
  • CVE-2026-4611552 days apartblock: add pgmap check to biovec_phys_mergeable
    39Monitor
  • CVE-2026-4311474 days apartnetfilter: nft_set_pipapo_avx2: don't return non-matching entry on expiry
    37Monitor
  • CVE-2026-641060 days apartKVM: arm64: vgic-its: Reject restored DTE with out-of-range num_eventid_bits
    36Monitor

National notice (Türkiye Cybersecurity Directorate / USOM)

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

All national notices →

Not on record for this CVE: patch commit or PR link · researcher credit · public bounty program.

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)

CWE-20 · Improper Input Validation

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.

References

Show all references (5 more)

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

All records