7.8 High

In the Linux kernel, the following vulnerability has been resolved: tracing/histograms: Reject non-stacktrace fields for synthetic…

CVE-2026-99163

In the Linux kernel, the following vulnerability has been resolved: tracing/histograms: Reject non-stacktrace fields for synthetic stacktrace fields In checksynthfield(), when a synthetic event field is a stacktrace (field->isstack) and the histogram field is not a "long[" stacktrace array, validation falls through to the generic size and signedness comparison. Because parsesynthfield() sets a stacktrace field's type to "dataloc unsigned long[]", its size is sizeof(u64) and synthfieldsigned() marks it as signed. Consequently, any 8-byte signed scalar histogram field passes the fallback check, and its scalar value is subsequently dereferenced as a kernel stacktrace pointer in getfieldsize() and tracestack(). Furthermore, checking strstr(histfield->type, "long[") is insufficient because tracepoint fields defined with bitmask() or relbitmask() also have type "dataloc unsigned long[]" or "relloc unsigned long[]", whilst createhistfield() treats them as 4-byte scalar values without HISTFIELDFLSTACKTRACE. Propagate HISTFIELDFLSTACKTRACE to variable references and field variables (whilst excluding variable aliases from per-element stacktrace capture), and reject any mismatch between…

Assessment

CVSS: 7.8 (v3.1)
Severity: High
EPSS: 0.17% chance of exploitation in the next 30 days
Known exploited: Not listed in CISA KEV
Exploit availability: Nothing found in Exploit-DB, Metasploit, Nuclei or public PoC repositories
Published: 28 October 2026
Last updated: 31 October 2026
Affected: Linux
Assigner: Linux

CVSS vectorCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

At the source

EUVD (ENISA)

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