Bug 2565258 (CVE-2026-99236)

Summary:	CVE-2026-99236 kernel: kernel: privilege escalation via incomplete event filter expressions
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security DevOps Team <prodsec-dev>
Status:	NEW ---	QA Contact:
Severity:	high	Docs Contact:
Priority:	high
Version:	unspecified	CC:	akhatavk, aos-team-art-private, asdas, dpaolell, jdelft, jupierce, lgarciaa, mbiarnes, ppalepu, ppostler, prdhamdh, rhel-process-autobot, sghai, sidsharm, suppawar, vlaad, watson-tool-maintainers
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	---
Doc Text:	A flaw was found in the Linux kernel. A local user can trigger out-of-bounds memory access to achieve privilege escalation or arbitrary code execution by submitting an incomplete event filter expression containing trailing logical operators. Alternatively, exploiting this flaw can expose sensitive kernel memory or crash the operating system, resulting in a Denial of Service (DoS).	Story Points:	---
Clone Of:		Environment:
Last Closed:		Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2026-11-02 16:32:22 UTC

In the Linux kernel, the following vulnerability has been resolved:

tracing: Reject incomplete event filter expressions

A non-empty expression normally finishes in predicate_parse()'s inner
loop, which resolves the pending logical operators before jumping to
finalization. If the input ends after an operator, possibly followed by
unary '!' tokens, the outer loop instead falls through with unresolved
operator state.

For example, "common_pid == 1 || common_pid == 2 &&" leaves
prog[0].target equal to -1. The second pass then reads prog[-1] before
the forward-jump check can reject it. Depending on adjacent slab
contents, it can also copy an out-of-bounds word into a branch target
that passes the forward-only check. A self-targeted perf tracepoint
counting event can reach this path through PERF_EVENT_IOC_SET_FILTER.

Reject the outer-loop fallthrough when a predicate has already been
parsed. This ensures that non-empty expressions only reach finalization
after the inner loop has resolved their operators. Keep the existing
no-filter error for input that has no predicates. Add a regression test
for trailing logical operators and unary negations.