Bug 2492291 (CVE-2026-53095)
| Summary: | CVE-2026-53095 kernel: bpf: Fix abuse of kprobe_write_ctx via freplace | ||
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| Product: | [Other] Security Response | Reporter: | OSIDB Bzimport <bzimport> |
| Component: | vulnerability | Assignee: | Product Security <prodsec-ir-bot> |
| Status: | NEW --- | QA Contact: | |
| Severity: | medium | Docs Contact: | |
| Priority: | medium | ||
| Version: | unspecified | CC: | rhel-process-autobot, 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. This vulnerability allows for the abuse of the `kprobe_write_ctx` mechanism through `freplace` in Berkeley Packet Filter (BPF) kprobe programs. A local attacker could exploit this by attaching a `freplace` program to a `kprobe` program that is attached to a kernel function. This could lead to the modification of the kernel function's arguments, specifically setting the first argument to zero, potentially causing unexpected system behavior or impacting data integrity.
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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: | |||
In the Linux kernel, the following vulnerability has been resolved: bpf: Fix abuse of kprobe_write_ctx via freplace uprobe programs are allowed to modify struct pt_regs. Since the actual program type of uprobe is KPROBE, it can be abused to modify struct pt_regs via kprobe+freplace when the kprobe attaches to kernel functions. For example, SEC("?kprobe") int kprobe(struct pt_regs *regs) { return 0; } SEC("?freplace") int freplace_kprobe(struct pt_regs *regs) { regs->di = 0; return 0; } freplace_kprobe prog will attach to kprobe prog. kprobe prog will attach to a kernel function. Without this patch, when the kernel function runs, its first arg will always be set as 0 via the freplace_kprobe prog. To fix the abuse of kprobe_write_ctx=true via kprobe+freplace, disallow attaching freplace programs on kprobe programs with different kprobe_write_ctx values.