Linux Kernel Mediatek Vcodec NULL Deref via IPI Handler: mutex->spinlock fix
CVE-2025-71140 Published on January 14, 2026
media: mediatek: vcodec: Use spinlock for context list protection lock
In the Linux kernel, the following vulnerability has been resolved:
media: mediatek: vcodec: Use spinlock for context list protection lock
Previously a mutex was added to protect the encoder and decoder context
lists from unexpected changes originating from the SCP IP block, causing
the context pointer to go invalid, resulting in a NULL pointer
dereference in the IPI handler.
Turns out on the MT8173, the VPU IPI handler is called from hard IRQ
context. This causes a big warning from the scheduler. This was first
reported downstream on the ChromeOS kernels, but is also reproducible
on mainline using Fluster with the FFmpeg v4l2m2m decoders. Even though
the actual capture format is not supported, the affected code paths
are triggered.
Since this lock just protects the context list and operations on it are
very fast, it should be OK to switch to a spinlock.
Products Associated with CVE-2025-71140
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Affected Versions
Linux:- Version 0a2dc707aa42214f9c4827bd57e344e29a0841d6 and below 2c1ea6214827041f548279c9eda341eda0cc8351 is affected.
- Version 6467cda18c9f9b5f2f9a0aa1e2861c653e41f382 and below b92c19675f632a41af1222027a231bc2b7efa7ed is affected.
- Version 6467cda18c9f9b5f2f9a0aa1e2861c653e41f382 and below 3e858938b0e659f6ec9ddcf853a87f1c5c3f44e1 is affected.
- Version 6467cda18c9f9b5f2f9a0aa1e2861c653e41f382 and below a5844227e0f030d2af2d85d4aed10c5eca6ca176 is affected.
- Version 23aaf824121055ba81b55f75444355bd83c8eb38 is affected.
- Version 41671f0c0182b2bae74ca7e3b0f155559e3e2fc5 is affected.
- Version 51c84a8aac6e3b59af2b0e92ba63cabe2e641a2d is affected.
- Version 6.9 is affected.
- Before 6.9 is unaffected.
- Version 6.6.120, <= 6.6.* is unaffected.
- Version 6.12.64, <= 6.12.* is unaffected.
- Version 6.18.4, <= 6.18.* is unaffected.
- Version 6.19, <= * is unaffected.
Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.