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NVD / CVE Program· CNA Linux

CVE-2021-47305: dma-buf/sync_file: Don't leak fences on merge failure

MediumCVSS 5.5 · v3.1—No exploit Fix available

Noroxi assessment

Priority: Monitor (action score 22/100)

  • 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: 0.23% (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 0d514185ae792d3a1903c8e1a83899aa996705ce, 19edcd97727aae9362444a859a24d99a8730cb27, 19f51c2529339280d2c8c6427cd3e21ddf1ac3f8.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 0d514185ae792d3a1903c8e1a83899aa996705ce, 19edcd97727aae9362444a859a24d99a8730cb27, 19f51c2529339280d2c8c6427cd3e21ddf1ac3f8 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: dma-buf/sync_file: Don't leak fences on merge failure Each add_fence() call does a dma_fence_get() on the relevant fence. In the error path, we weren't calling dma_fence_put() so all those fences got leaked. Also, in the krealloc_array failure case, we weren't freeing the fences array. Instead, ensure that i and fences are always zero-initialized and dma_fence_put() all the fences and kfree(fences) on every error path.

Published
May 21, 2024
Updated
Jun 17, 2026
EPSS
0.2% · 15th percentile

Report tools

JSON

Action score

22

Monitor

Low priority for now.

CVSS
22 / 40 · 5.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.2%

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-2021-47305

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

    • 4.9affected
    • a02b9dc90d844cc7df7b63264e7920cc425052d9 and later · before 19f51c2529339280d2c8c6427cd3e21ddf1ac3f8affected · git
    • a02b9dc90d844cc7df7b63264e7920cc425052d9 and later · before e0355a0ad31a1d677b2a4514206de4902bd550e8affected · git
    • a02b9dc90d844cc7df7b63264e7920cc425052d9 and later · before 41f45e91c92c8480242ea448d54e28c753b13902affected · git
    • a02b9dc90d844cc7df7b63264e7920cc425052d9 and later · before 0d514185ae792d3a1903c8e1a83899aa996705ceaffected · git
    • a02b9dc90d844cc7df7b63264e7920cc425052d9 and later · before 19edcd97727aae9362444a859a24d99a8730cb27affected · git
    • a02b9dc90d844cc7df7b63264e7920cc425052d9 and later · before ffe000217c5068c5da07ccb1c0f8cce7ad767435affected · git
    • before 4.9not affected · semver
    • 4.14.241 and later · up to and including 4.14.*not affected · semver
    • 4.19.199 and later · up to and including 4.19.*not affected · semver
Affected versions · NVD (6)

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

  • linux linux kernel4.9 and later · before 4.14.241
  • linux linux kernel4.15 and later · before 4.19.199
  • linux linux kernel4.20 and later · before 5.4.135
  • linux linux kernel5.5 and later · before 5.10.53
  • linux linux kernel5.11 and later · before 5.13.5
  • linux linux kernel5.14

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 5.14.6-15.14.6-1

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-2021-47303May 21, 2024 · bpf: Track subprog poke descriptors correctly and fix use-after-free
    31Monitor
  • ← EarlierCVE-2021-47304May 21, 2024 · tcp: fix tcp_init_transfer() to not reset icsk_ca_initialized
    22Monitor
  • Later →CVE-2021-47306May 21, 2024 · net: fddi: fix UAF in fza_probe
    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 / packageFixed versionSource
Linux Linux0d514185ae792d3a1903c8e1a83899aa996705ceVendor (CNA)
Linux Linux19edcd97727aae9362444a859a24d99a8730cb27Vendor (CNA)
Linux Linux19f51c2529339280d2c8c6427cd3e21ddf1ac3f8Vendor (CNA)
Linux Linux41f45e91c92c8480242ea448d54e28c753b13902Vendor (CNA)
Linux Linuxe0355a0ad31a1d677b2a4514206de4902bd550e8Vendor (CNA)
Linux Linuxffe000217c5068c5da07ccb1c0f8cce7ad767435Vendor (CNA)
debian:linux5.14.6-1 · 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.

Variant candidates

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

  • CVE-2023-2156378 days apartA flaw was found in the networking subsystem of the Linux kernel within the handling of the RPL protocol.
    32Monitor
  • CVE-2023-5262156 days apartbpf: Check rcu_read_lock_trace_held() before calling bpf map helpers
    31Monitor
  • CVE-2025-39803482 days apartscsi: ufs: core: Remove WARN_ON_ONCE() call from ufshcd_uic_cmd_compl()
    31Monitor
  • CVE-2021-473150 days apartmemory: fsl_ifc: fix leak of IO mapping on probe failure
    22Monitor
  • CVE-2021-473510 days apartubifs: Fix races between xattr_{set|get} and listxattr operations
    22Monitor
  • CVE-2023-528310 days apartcpu/hotplug: Don't offline the last non-isolated CPU
    22Monitor

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: EPSS history · 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
none
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
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

CWE-617 · Reachable Assertion

CVSS vector

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

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

References

Show all references (5 more)

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

All records