# CVE-2024-35871: linux: In the Linux kernel, the following vulnerability has been resolved:  riscv: process: Fix kernel gp leakage  childregs...

CVE-2024-35871 is fixed in linux on 1 platform, first by DEBIAN-CVE-2024-35871, released May 19, 2024. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2024-35871
- Priority: High
- CVSS: 7.1 (high)
- EPSS: 0.0027
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: May 19, 2024

## Description

In the Linux kernel, the following vulnerability has been resolved:  riscv: process: Fix kernel gp leakage  childregs represents the registers which are active for the new thread in user context. For a kernel thread, childregs->gp is never used since the kernel gp is not touched by switch_to. For a user mode helper, the gp value can be observed in user space after execve or possibly by other means.  [From the email thread]  The /* Kernel thread */ comment is somewhat inaccurate in that it is also used for user_mode_helper threads, which exec a user process, e.g. /sbin/init or when /proc/sys/kernel/core_pattern is a pipe. Such threads do not have PF_KTHREAD set and are valid targets for ptrace etc. even before they exec.  childregs is the *user* context during syscall execution and it is observable from userspace in at least five ways:  1. kernel_execve does not currently clear integer registers, so the starting    register state for PID 1 and other user processes started by the kernel has    sp = user stack, gp = kernel __global_pointer$, all other integer registers    zeroed by the memset in the patch comment.     This is a bug in its own right, but I'm unwilling to bet that it is the only    way to exploit the issue addressed by this patch.  2. ptrace(PTRACE_GETREGSET): you can PTRACE_ATTACH to a user_mode_helper thread    before it execs, but ptrace requires SIGSTOP to be delivered which can only    happen at user/kernel boundaries.  3. /proc/*/task/*/syscall: this is perfectly happy to read pt_regs for    user_mode_helpers before the exec completes, but gp is not one of the    registers it returns.  4. PERF_SAMPLE_REGS_USER: LOCKDOWN_PERF normally prevents access to kernel    addresses via PERF_SAMPLE_REGS_INTR, but due to this bug kernel addresses    are also exposed via PERF_SAMPLE_REGS_USER which is permitted under    LOCKDOWN_PERF. I have not attempted to write exploit code.  5. Much of the tracing infrastructure allows access to user registers. I have    not attempted to determine which forms of tracing allow access to user    registers without already allowing access to kernel registers.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 12.15 (bookworm) | 6.1.85-1 | [DEBIAN-CVE-2024-35871](https://patchblox.com/security/data/fix/linux/debian-cve-2024-35871.md) | May 19, 2024 |
| Linux | linux Debian 13.5 (trixie) | 6.8.9-1 | [DEBIAN-CVE-2024-35871](https://patchblox.com/security/data/fix/linux/debian-cve-2024-35871.md) | May 19, 2024 |
| Linux | linux Debian 14 | 6.8.9-1 | [DEBIAN-CVE-2024-35871](https://patchblox.com/security/data/fix/linux/debian-cve-2024-35871.md) | May 19, 2024 |

---

Data as of 2026-11-08T00:53:09Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

Free to use with attribution: show "Data: Patchblox Patch Radar" with a link to https://patchblox.com/security/patch-radar. Terms, including what needs a written agreement: https://patchblox.com/security/patch-radar/use-the-data

Product names, logos and trademarks shown on Patch Radar belong to their respective owners. They are used only to identify the software each security fix applies to and to help readers find their platform. Their use does not imply any affiliation with, or endorsement by, those owners, and Patchblox is not affiliated with any of them.