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NVD / CVE Program· CNA Linux

CVE-2021-47280: drm: Fix use-after-free read in drm_getunique()

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: 0.18% (FIRST EPSS).
  • Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. Special conditions such as timing or configuration are required.
  • Fixed version: Linux Linux 17dab9326ff263c62dab1dbac4492e2938a049e4, 491d52e0078860b33b6c14f0a7ac74ca1b603bd6, 7d233ba700ceb593905ea82b42dadb4ec8ef85e9.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 17dab9326ff263c62dab1dbac4492e2938a049e4, 491d52e0078860b33b6c14f0a7ac74ca1b603bd6, 7d233ba700ceb593905ea82b42dadb4ec8ef85e9 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: Fix use-after-free read in drm_getunique() There is a time-of-check-to-time-of-use error in drm_getunique() due to retrieving file_priv->master prior to locking the device's master mutex. An example can be seen in the crash report of the use-after-free error found by Syzbot: https://syzkaller.appspot.com/bug?id=148d2f1dfac64af52ffd27b661981a540724f803 In the report, the master pointer was used after being freed. This is because another process had acquired the device's master mutex in drm_setmaster_ioctl(), then overwrote fpriv->master in drm_new_set_master(). The old value of fpriv->master was subsequently freed before the mutex was unlocked. To fix this, we lock the device's master mutex before retrieving the pointer from from fpriv->master. This patch passes the Syzbot reproducer test.

HighCVSS 7.0 · v3.1—No exploit Fix available
Published
May 21, 2024
Updated
Jun 17, 2026
EPSS
0.1% · 7th percentile

Report tools

JSON

Action score

28

Monitor

Low priority for now.

CVSS
28 / 40 · 7.0 / 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.

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-2021-47280

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

Affected versions

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

  • linux linux kernelbefore 4.14.237
  • linux linux kernel4.15 and later · before 4.19.195
  • linux linux kernel4.20 and later · before 5.4.126
  • linux linux kernel5.5 and later · before 5.10.44
  • linux linux kernel5.11 and later · before 5.12.11
  • linux linux kernel5.13

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

    • 4.11affected
    • 5acc614ac47465fee6375a9af4740f618830762d and later · before 17dab9326ff263c62dab1dbac4492e2938a049e4affected · git
    • 5acc614ac47465fee6375a9af4740f618830762d and later · before 7d233ba700ceb593905ea82b42dadb4ec8ef85e9affected · git
    • 5acc614ac47465fee6375a9af4740f618830762d and later · before b246b4c70c1250e7814f409b243000f9c0bf79a3affected · git
    • 5acc614ac47465fee6375a9af4740f618830762d and later · before 491d52e0078860b33b6c14f0a7ac74ca1b603bd6affected · git
    • 5acc614ac47465fee6375a9af4740f618830762d and later · before f773f8cccac13c7e7bbd9182e7996c727742488eaffected · git
    • 5acc614ac47465fee6375a9af4740f618830762d and later · before b436acd1cf7fac0ba987abd22955d98025c80c2baffected · git
    • before 4.11not affected · semver
    • 4.14.237 and later · up to and including 4.14.*not affected · semver
    • 4.19.195 and later · up to and including 4.19.*not affected · semver

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 5.10.46-15.10.46-1

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-2021-47278May 21, 2024 · bus: mhi: pci_generic: Fix possible use-after-free in mhi_pci_remove()
    31Monitor
  • ← EarlierCVE-2021-47279May 21, 2024 · usb: misc: brcmstb-usb-pinmap: check return value after calling platform_get_resource()
    22Monitor
  • Later →CVE-2021-47281May 21, 2024 · ALSA: seq: Fix race of snd_seq_timer_open()
    28Monitor

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 Linux17dab9326ff263c62dab1dbac4492e2938a049e4Vendor (CNA)
Linux Linux491d52e0078860b33b6c14f0a7ac74ca1b603bd6Vendor (CNA)
Linux Linux7d233ba700ceb593905ea82b42dadb4ec8ef85e9Vendor (CNA)
Linux Linuxb246b4c70c1250e7814f409b243000f9c0bf79a3Vendor (CNA)
Linux Linuxb436acd1cf7fac0ba987abd22955d98025c80c2bVendor (CNA)
Linux Linuxf773f8cccac13c7e7bbd9182e7996c727742488eVendor (CNA)
debian:linux5.10.46-1 · 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.

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.

  • CVE-2025-38352427 days apartposix-cpu-timers: fix race between handle_posix_cpu_timers() and posix_cpu_timer_del()KEV
    61This week
  • CVE-2023-2007393 days apartThe specific flaw exists within the DPT I2O Controller driver.
    31Monitor
  • CVE-2024-2697420 days apartcrypto: qat - resolve race condition during AER recovery
    28Monitor
  • CVE-2024-4388292 days apartexec: Fix ToCToU between perm check and set-uid/gid usage
    28Monitor
  • CVE-2024-50234172 days apartwifi: iwlegacy: Clear stale interrupts before resuming device
    28Monitor
  • CVE-2023-1295328 days apartPrivilege escalation with IO_RING_OP_CLOSE in the Linux Kernel
    28Monitor

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.
  • Special conditions such as timing or configuration are required.

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
High
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

CWE-367 · Time-of-check Time-of-use (TOCTOU) Race Condition

CVSS vector

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

nvd-primary

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. Fix✗ → ✓

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

References

Show all references (5 more)

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

All records