CVE-2026-99233

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CVE-2026-99233

Summary: tracing/histograms: Verify event_call identity when updating synth_event refcount

Details: In the Linux kernel, the following vulnerability has been resolved: tracing/histograms: Verify event_call identity when updating synth_event refcount In event_hist_trigger_parse() and hist_unreg_all(), the histogram registration and unregistration paths look up find_synth_event() using trace_event_name(file->event_call) and adjust se->ref if a match is found. Because find_synth_event() only compares the event basename, registering or removing a histogram on a non-synthetic trace event whose basename matches a synthetic event erroneously modifies the synthetic event's reference count. If a histogram is registered on the non-synthetic event before the synthetic event is created and removed afterwards, se->ref is decremented without a matching increment, allowing the synthetic event to be freed while an active histogram action still holds a pointer to it. Introduce find_synth_event_call() to verify that &se->call matches file->event_call before adjusting se->ref.

References: https://git.kernel.org/stable/c/06e816bed499fe47f39f12044382cc5d064485fb, https://git.kernel.org/stable/c/23b4106e8b35823acc79e206c7745f55b9cfd78b, https://git.kernel.org/stable/c/3403d9bb27ebc3572bd048620746b4414e073bf9, https://git.kernel.org/stable/c/381f543ed35c434d5b707369aa5dcd69ecf440af, https://git.kernel.org/stable/c/4472579bd1c83708b6fe623c870cdf728e947205, https://git.kernel.org/stable/c/5597bb8db6855fcb97a67196d227fea359bcd81c, https://git.kernel.org/stable/c/cf4e31d5da80fae4c9cdbe7af55b7c3ad213f0e4, https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/99xxx/CVE-2026-99233.json, https://nvd.nist.gov/vuln/detail/CVE-2026-99233, https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git