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NVD / CVE Program· CNA Linux

CVE-2026-74463: i2c: jz4780: Cache host clock rate at probe to prevent CCF prepare_lock deadlock

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 14429dc1c756c35e106f01ff09cadccb82f5531d, 19b783335d62e7a2367436a6e1f1b37da1878360, aa1944b52d6492c48bdd17046578aa0d953546e6.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 14429dc1c756c35e106f01ff09cadccb82f5531d, 19b783335d62e7a2367436a6e1f1b37da1878360, aa1944b52d6492c48bdd17046578aa0d953546e6 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: i2c: jz4780: Cache host clock rate at probe to prevent CCF prepare_lock deadlock Fix a severe AB/BA deadlock between the Common Clock Framework (CCF) and the I2C adapter lock, which triggers when an I2C-controlled clock generator client (like the Si5351) is registered or modified under the CCF. During an i2c client clock (generator) frequency change, the CCF acquires its global 'prepare_lock' mutex and the driver calls i2c_transfer() to update the client's chip registers, stalling for the adapter's I2C bus lock. Concurrently, an independent, parallel transfer on the same bus (e.g., a GPIO expander handling LEDs) can hold the I2C adapter lock. Inside this parallel transfer path, jz4780_i2c_set_speed() calls clk_get_rate() on the host controller's input clock to calculate bus timings. This call attempts to acquire the blocked CCF 'prepare_lock', creating a circular dependency that freezes the system. The jz4780 host controller clock itself is static and never changes at runtime. However, calling clk_get_rate() inside the active transfer path introduces an unnecessary dependency on the CCF internal locks. Eliminate this synchronous clk_get_rate() call from the active transfer path by caching the static host peripheral clock rate once - inside the private jz4780_i2c structure during jz4780_i2c_probe(). Update jz4780_i2c_set_speed() to use this cached value, safely decoupling active I2C transactions from the CCF internal locks without any risk of stale timings. Assisted-by web based Google AI (pinpointing the bug and writing the message).

—No exploit Fix available
Published
Aug 15, 2026
Updated
Aug 19, 2026
EPSS
0.1% · 7th 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

    • 4.1affected
    • ba92222ed63a12d09120df9b92f56cc990abac19 and later · before cc111696ef420f6bb552b2526530067977f0b406affected · git
    • ba92222ed63a12d09120df9b92f56cc990abac19 and later · before f96a719d9f8a797105ec5cacf568ab128e33391faffected · git
    • ba92222ed63a12d09120df9b92f56cc990abac19 and later · before deffad5bb4f8b4f09e46252f24754ddc9960b244affected · git
    • ba92222ed63a12d09120df9b92f56cc990abac19 and later · before 14429dc1c756c35e106f01ff09cadccb82f5531daffected · git
    • ba92222ed63a12d09120df9b92f56cc990abac19 and later · before b6cb47e186abba85a3b08aa3023067ab82577286affected · git
    • ba92222ed63a12d09120df9b92f56cc990abac19 and later · before 19b783335d62e7a2367436a6e1f1b37da1878360affected · git
    • ba92222ed63a12d09120df9b92f56cc990abac19 and later · before aa1944b52d6492c48bdd17046578aa0d953546e6affected · git
    • ba92222ed63a12d09120df9b92f56cc990abac19 and later · before d99607c888f26e8a4e9fe9772860cef4aff86bb4affected · git
    • before 4.1not 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 6.12.107-1~deb12u16.12.107-1~deb12u1
Debian:13linuxbefore 6.12.105-16.12.105-1
Debian:14linuxbefore 7.1.8-17.1.8-1

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-2026-74459Aug 15, 2026 · can: etas_es58x: es58x_read_bulk_callback(): fix RX buffer leak on URB resubmit failure
    0Monitor
  • ← EarlierCVE-2026-74462Aug 15, 2026 · i2c: imx: mark I2C adapter when hardware is powered down
    0Monitor
  • Later →CVE-2026-74468Aug 15, 2026 · gpio: pch: use raw_spinlock_t for the register lock
    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 Linux14429dc1c756c35e106f01ff09cadccb82f5531dVendor (CNA)
Linux Linux19b783335d62e7a2367436a6e1f1b37da1878360Vendor (CNA)
Linux Linuxaa1944b52d6492c48bdd17046578aa0d953546e6Vendor (CNA)
Linux Linuxb6cb47e186abba85a3b08aa3023067ab82577286Vendor (CNA)
Linux Linuxcc111696ef420f6bb552b2526530067977f0b406Vendor (CNA)
Linux Linuxd99607c888f26e8a4e9fe9772860cef4aff86bb4Vendor (CNA)
Linux Linuxdeffad5bb4f8b4f09e46252f24754ddc9960b244Vendor (CNA)
Linux Linuxf96a719d9f8a797105ec5cacf568ab128e33391fVendor (CNA)
debian:linux6.1.187-1 · Debian:12Package registry (OSV)
debian:linux-6.126.12.107-1~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✗ → ✓

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

References

Show all references (7 more)

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

All records