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NVD / CVE Program· CNA Linux

CVE-2026-93168: dmaengine: xilinx_dma: Fix CPU stall in xilinx_dma_poll_timeout

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: 0.17% (FIRST EPSS).
  • Fixed version: Linux Linux 2ba67aa183a3ce174d534425b67eda84f6e3c896, 4237b5cc181a17f5a2a797655c1ce2c64e01c550, 8b5654d317277e6e505c23f8fa7e415237fefc7f.

Low priority for now. Upgrade to Linux Linux 2ba67aa183a3ce174d534425b67eda84f6e3c896, 4237b5cc181a17f5a2a797655c1ce2c64e01c550, 8b5654d317277e6e505c23f8fa7e415237fefc7f 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: dmaengine: xilinx_dma: Fix CPU stall in xilinx_dma_poll_timeout Currently when calling xilinx_dma_poll_timeout with delay_us=0 and a condition that is never fulfilled, the CPU busy-waits for prolonged time and the timeout triggers only with a massive delay causing a CPU stall. This happens due to a huge underestimation of wall clock time in poll_timeout_us_atomic. Commit 7349a69cf312 ("iopoll: Do not use timekeeping in read_poll_timeout_atomic()") changed the behavior to no longer use ktime_get at the expense of underestimation of wall clock time which appears to be very large for delay_us=0. Instead of timing out after approximately XILINX_DMA_LOOP_COUNT microseconds, the timeout takes XILINX_DMA_LOOP_COUNT * 1000 * (time that the overhead of the for loop in poll_timeout_us_atomic takes) which is in the range of several minutes for XILINX_DMA_LOOP_COUNT=1000000. Fix this by using a non-zero value for delay_us. Use delay_us=10 to keep the delay in the hot path of starting DMA transfers minimal but still avoid CPU stalls in case of unexpected hardware failures. One-off measurement with delay_us=0 causes the cpu to busy wait around 7 minutes in the timeout case. After applying this patch with delay_us=10 the measured timeout was 1053428 microseconds which is roughly equivalent to the expected 1000000 microseconds specified in XILINX_DMA_LOOP_COUNT. Add a constant XILINX_DMA_POLL_DELAY_US for delay_us value.

—No exploit Fix available
Published
Sep 17, 2026
Updated
Oct 30, 2026
EPSS
0.1% · 6th 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

    • 4.6affected
    • 9495f2648287029fb5545c34a0fa318426ebe84c and later · before 4237b5cc181a17f5a2a797655c1ce2c64e01c550affected · git
    • 9495f2648287029fb5545c34a0fa318426ebe84c and later · before 2ba67aa183a3ce174d534425b67eda84f6e3c896affected · git
    • 9495f2648287029fb5545c34a0fa318426ebe84c and later · before c30a26d4987a01e619449bf170f584c007e07d75affected · git
    • 9495f2648287029fb5545c34a0fa318426ebe84c and later · before f786e7b3adbf3bd14964a1cedf9d55b6ad91dcd7affected · git
    • 9495f2648287029fb5545c34a0fa318426ebe84c and later · before 8b5654d317277e6e505c23f8fa7e415237fefc7faffected · git
    • 9495f2648287029fb5545c34a0fa318426ebe84c and later · before aa99c4d1d63bbc26a5fc4c667d89b2595743c19daffected · git
    • before 4.6not affected · semver
    • 6.1.191 and later · up to and including 6.1.*not affected · semver
    • 6.6.160 and later · up to and including 6.6.*not affected · semver

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12linuxfrom 0—
Debian:13linuxbefore 6.12.115-26.12.115-2
Debian:14linuxbefore 7.2.6-17.2.6-1

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-2026-93166Sep 17, 2026 · wifi: rtw89: debug: fix off by on in rtw89_ppdu_str()
    0Monitor
  • ← EarlierCVE-2026-93167Sep 17, 2026 · csky: Fix a4/a5 restoration in syscall trace path
    0Monitor
  • Later →CVE-2026-93169Sep 17, 2026 · dmaengine: zynqmp_dma: fix race between runtime PM and device removal
    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 Linux2ba67aa183a3ce174d534425b67eda84f6e3c896Vendor (CNA)
Linux Linux4237b5cc181a17f5a2a797655c1ce2c64e01c550Vendor (CNA)
Linux Linux8b5654d317277e6e505c23f8fa7e415237fefc7fVendor (CNA)
Linux Linuxaa99c4d1d63bbc26a5fc4c667d89b2595743c19dVendor (CNA)
Linux Linuxc30a26d4987a01e619449bf170f584c007e07d75Vendor (CNA)
Linux Linuxf786e7b3adbf3bd14964a1cedf9d55b6ad91dcd7Vendor (CNA)
debian:linux6.12.115-2 · Debian:13Package registry (OSV)
debian:linux7.2.6-1 · Debian:14Package 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

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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

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 (5 more)

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

All records