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NVD / CVE Program· CNA Linux

CVE-2026-64590: dma-buf/udmabuf: skip redundant cpu sync to fix cacheline EEXIST warning

Noroxi assessment

Priority: Monitor (action score 0/100)

  • 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: 0.16% (FIRST EPSS).
  • Fixed version: Linux Linux 01126abc11bcc6a45b664293b0b5df715be911d7, 0449a6583c0ee76778d314e4e82f166fc97fa9d8, 0db56e7eae932f8e2f3eb44ad1a63633d8f504f8; azl3 kernel 6.6.145.2-1 on Azure Linux 3.0 6.6.150.1-1.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 01126abc11bcc6a45b664293b0b5df715be911d7, 0449a6583c0ee76778d314e4e82f166fc97fa9d8, 0db56e7eae932f8e2f3eb44ad1a63633d8f504f8; azl3 kernel 6.6.145.2-1 on Azure Linux 3.0 6.6.150.1-1 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: dma-buf/udmabuf: skip redundant cpu sync to fix cacheline EEXIST warning When CONFIG_DMA_API_DEBUG_SG is enabled, importing a udmabuf into a DRM driver (e.g. amdgpu for video playback in GNOME Videos / Showtime) triggers a spurious warning: DMA-API: amdgpu 0000:03:00.0: cacheline tracking EEXIST, \ overlapping mappings aren't supported WARNING: kernel/dma/debug.c:619 at add_dma_entry+0x473/0x5f0 The call chain is: amdgpu_cs_ioctl -> amdgpu_ttm_backend_bind -> dma_buf_map_attachment -> [udmabuf] map_udmabuf -> get_sg_table -> dma_map_sgtable(dev, sg, direction, 0) // attrs=0 -> debug_dma_map_sg -> add_dma_entry -> EEXIST This happens because udmabuf builds a per-page scatter-gather list via sg_set_folio(). When begin_cpu_udmabuf() has already created an sg table mapped for the misc device, and an importer such as amdgpu maps the same pages for its own device via map_udmabuf(), the DMA debug infrastructure sees two active mappings whose physical addresses share cacheline boundaries and warns about the overlap. The DMA_ATTR_SKIP_CPU_SYNC flag suppresses this check in add_dma_entry() because it signals that no CPU cache maintenance is performed at map/unmap time, making the cacheline overlap harmless. All other major dma-buf exporters already pass this flag: - drm_gem_map_dma_buf() passes DMA_ATTR_SKIP_CPU_SYNC - amdgpu_dma_buf_map() passes DMA_ATTR_SKIP_CPU_SYNC The CPU sync at map/unmap time is also redundant for udmabuf: begin_cpu_udmabuf() and end_cpu_udmabuf() already perform explicit cache synchronization via dma_sync_sgtable_for_cpu/device() when CPU access is requested through the dma-buf interface. Pass DMA_ATTR_SKIP_CPU_SYNC to dma_map_sgtable() and dma_unmap_sgtable() in udmabuf to suppress the spurious warning and skip the redundant sync.

—No exploit Fix available
Published
Aug 6, 2026
Updated
Aug 23, 2026
EPSS
0.1% · 5th percentile
CWE
—

Report tools

JSON

Action score

0

Monitor

Low priority for now.

CVSS
0 / 40 · —
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

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Noroxi analysis

What does it mean in your environment?

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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

    • 5.6affected
    • 284562e1f34874e267d4f499362c3816f8f6bc3f and later · before 4a7c644e632741c2a3116a0d3da6c11de957a6baaffected · git
    • 284562e1f34874e267d4f499362c3816f8f6bc3f and later · before 01126abc11bcc6a45b664293b0b5df715be911d7affected · git
    • 284562e1f34874e267d4f499362c3816f8f6bc3f and later · before dd7f1e572f44d3d039dc77e3989f537196c3bf52affected · git
    • 284562e1f34874e267d4f499362c3816f8f6bc3f and later · before 0db56e7eae932f8e2f3eb44ad1a63633d8f504f8affected · git
    • 284562e1f34874e267d4f499362c3816f8f6bc3f and later · before d6552f5cff795d60e629f37513ecf23d88fd2f82affected · git
    • 284562e1f34874e267d4f499362c3816f8f6bc3f and later · before 34696563461c9a23177feb6d8aff43f4c0510278affected · git
    • 284562e1f34874e267d4f499362c3816f8f6bc3f and later · before 0449a6583c0ee76778d314e4e82f166fc97fa9d8affected · git
    • 284562e1f34874e267d4f499362c3816f8f6bc3f and later · before 504e2b4ab97a51d56d966cd36d0997ad30b65b2daffected · git
    • before 5.6not affected · semver

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.187-16.1.187-1
Debian:12linux-6.12before 6.12.100-1~deb12u16.12.100-1~deb12u1
Debian:13linuxbefore 6.12.96-16.12.96-1
Debian:14linuxbefore 7.1.4-17.1.4-1

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-2026-64588Aug 6, 2026 · fuse-uring: fix data races on ring->ready
    31Monitor
  • ← EarlierCVE-2026-64589Aug 6, 2026 · i2c: core: fix NULL-deref on adapter registration failure
    0Monitor
  • Later →CVE-2026-64591Aug 6, 2026 · iommu/vt-d: Avoid WARNING in sva unbind path
    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 Linux01126abc11bcc6a45b664293b0b5df715be911d7Vendor (CNA)
Linux Linux0449a6583c0ee76778d314e4e82f166fc97fa9d8Vendor (CNA)
Linux Linux0db56e7eae932f8e2f3eb44ad1a63633d8f504f8Vendor (CNA)
Linux Linux34696563461c9a23177feb6d8aff43f4c0510278Vendor (CNA)
Linux Linux4a7c644e632741c2a3116a0d3da6c11de957a6baVendor (CNA)
Linux Linux504e2b4ab97a51d56d966cd36d0997ad30b65b2dVendor (CNA)
Linux Linuxd6552f5cff795d60e629f37513ecf23d88fd2f82Vendor (CNA)
Linux Linuxdd7f1e572f44d3d039dc77e3989f537196c3bf52Vendor (CNA)
azl3 kernel 6.6.145.2-1 on Azure Linux 3.06.6.150.1-1 · CBL-Mariner ReleasesMicrosoft (MSRC)
debian:linux6.1.187-1 · Debian:12Package registry (OSV)
debian:linux-6.126.12.100-1~deb12u1 · 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.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

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).

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

No CVSS vector for this record, so attack conditions can't be derived.

Weakness class (CWE)

—

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✗ → ✓

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References

Show all references (7 more)

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

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