Bug 2507284 (CVE-2026-64354)

Summary: CVE-2026-64354 kernel: bpf: Validate BTF repeated field counts before expansion
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerability-draftAssignee: Product Security <prodsec-ir-bot>
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Priority: medium    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in the Linux kernel's BPF (Berkeley Packet Filter) component. This vulnerability, located in the `btf_repeat_fields()` function, is caused by an integer overflow when processing user-supplied BPF Type Format (BTF) data. A local attacker could exploit this flaw by providing a specially crafted BTF, leading to a heap out-of-bounds write. This could result in privilege escalation, allowing the attacker to gain elevated access to the system.
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Description OSIDB Bzimport 2026-07-25 10:14:30 UTC 
In the Linux kernel, the following vulnerability has been resolved:

bpf: Validate BTF repeated field counts before expansion

btf_parse_struct_metas() walks user-supplied BTF during BPF_BTF_LOAD,
and btf_repeat_fields() expands repeatable fields from array elements
into the fixed BTF_FIELDS_MAX scratch array used by btf_parse_fields().

The remaining-capacity check performs the expanded field count calculation
in u32. A malformed BTF can wrap that calculation, causing the check to
pass even when the expanded field count exceeds the scratch array
capacity. The following memcpy() can then write past the end of the
array.

Use checked addition and multiplication before copying repeated fields
and reject impossible counts.
Comment 1 TEJ RATHI 2026-07-27 08:09:27 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026072519-CVE-2026-64354-a771@gregkh/T