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CVE-2026-74463

UnknownEPSS 0.17%

Last modified

CVE-2026-74463 is a vulnerability of currently unknown severity. 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. EPSS estimates a 0.17% chance of exploitation in the next 30 days.

Description

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).

Metrics

EPSS Probability
0.17%

6.5th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
LinuxLinux>= ba92222ed63a12d09120df9b92f56cc990abac19, < cc111696ef420f6bb552b2526530067977f0b406; >= ba92222ed63a12d09120df9b92f56cc990abac19, < f96a719d9f8a797105ec5cacf568ab128e33391f; >= ba92222ed63a12d09120df9b92f56cc990abac19, < deffad5bb4f8b4f09e46252f24754ddc9960b244; >= ba92222ed63a12d09120df9b92f56cc990abac19, < 14429dc1c756c35e106f01ff09cadccb82f5531d; >= ba92222ed63a12d09120df9b92f56cc990abac19, < b6cb47e186abba85a3b08aa3023067ab82577286; >= ba92222ed63a12d09120df9b92f56cc990abac19, < 19b783335d62e7a2367436a6e1f1b37da1878360; >= ba92222ed63a12d09120df9b92f56cc990abac19, < aa1944b52d6492c48bdd17046578aa0d953546e6; >= ba92222ed63a12d09120df9b92f56cc990abac19, < d99607c888f26e8a4e9fe9772860cef4aff86bb4
LinuxLinux4.1

References

Timeline

Published
Last Modified
Status
Received

Frequently Asked Questions

What is CVE-2026-74463?
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).
How severe is CVE-2026-74463?
Severity scoring for CVE-2026-74463 is pending analysis. The EPSS model estimates a 0.17% probability of exploitation in the next 30 days.
How do I fix CVE-2026-74463?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST