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CVE-2025-71203

N/A Unknown

📋 TL;DR

This CVE addresses a speculative execution vulnerability in the RISC-V Linux kernel where an attacker could use a malicious syscall number to perform out-of-bounds memory access via cache side channels. This could potentially leak sensitive kernel data. Systems running affected RISC-V Linux kernel versions are vulnerable.

💻 Affected Systems

Products:
  • Linux kernel
Versions: Specific affected versions not specified in CVE description; check kernel commit history for exact ranges
Operating Systems: Linux distributions running on RISC-V architecture
Default Config Vulnerable: ⚠️ Yes
Notes: Only affects systems with RISC-V architecture; x86, ARM, and other architectures are not affected.

⚠️ Manual Verification Required

This CVE does not have specific version information in our database, so automatic vulnerability detection cannot determine if your system is affected.

Why? The CVE database entry doesn't specify which versions are vulnerable (no version ranges provided by the vendor/NVD).

🔒 Custom verification scripts are available for registered users. Sign up free to download automated test scripts.

Recommended Actions:
  1. Review the CVE details at NVD
  2. Check vendor security advisories for your specific version
  3. Test if the vulnerability is exploitable in your environment
  4. Consider updating to the latest version as a precaution

⚠️ Risk & Real-World Impact

🔴

Worst Case

An attacker could leak sensitive kernel memory contents including cryptographic keys, passwords, or other privileged data through cache timing side channels.

🟠

Likely Case

Information disclosure of kernel memory contents, potentially exposing system information or sensitive data.

🟢

If Mitigated

Minimal impact as speculative execution is prevented from accessing out-of-bounds memory locations.

🌐 Internet-Facing: LOW - Requires local access to execute syscalls, not directly exploitable over network.
🏢 Internal Only: MEDIUM - Local attackers or compromised users could exploit this to leak kernel data.

🎯 Exploit Status

Public PoC: ✅ No
Weaponized: UNKNOWN
Unauthenticated Exploit: ✅ No
Complexity: MEDIUM

Exploitation requires local access and knowledge of cache timing attacks; speculative execution vulnerabilities are complex to exploit reliably.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Kernel versions containing commits 25fd7ee7bf58ac3ec7be3c9f82ceff153451946c, 8b44e753795107a22ba31495686e83f4aca48f36, or c45848936ebdb4fcab92f8c39510db83c16d0239

Vendor Advisory: https://git.kernel.org/stable/c/25fd7ee7bf58ac3ec7be3c9f82ceff153451946c

Restart Required: Yes

Instructions:

1. Update Linux kernel to patched version from your distribution vendor. 2. Reboot system to load new kernel. 3. Verify kernel version after reboot.

🔧 Temporary Workarounds

Disable speculative execution features

linux

Disable CPU speculative execution features which may reduce performance but mitigate side-channel attacks

echo 1 > /sys/kernel/debug/sched/preempt

🧯 If You Can't Patch

  • Restrict local user access to minimize attack surface
  • Implement strict access controls and monitoring for local privilege escalation attempts

🔍 How to Verify

Check if Vulnerable:

Check kernel version and architecture: 'uname -r' and 'uname -m' - if RISC-V and kernel predates fix commits, likely vulnerable

Check Version:

uname -r

Verify Fix Applied:

Verify kernel version contains one of the fix commits: 'grep -r "array_index_nospec" /proc/kallsyms' or check kernel source for commit IDs

📡 Detection & Monitoring

Log Indicators:

  • Unusual syscall patterns from local users
  • Kernel oops or panic messages related to syscall handling

Network Indicators:

  • Not applicable - local vulnerability

SIEM Query:

source="kernel" AND (syscall_failure OR oops OR panic)

📊 Metadata

CVE ID: CVE-2025-71203
CVSS v3 Score: N/A (Unknown)
Published: February 14, 2026
Last Updated: February 18, 2026

🔗 References

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