CVE-2021-47486

System crash via NULL header free

Published May 22, 2024 · Updated May 11, 2026

NULL pointer dereference in the RISC-V BPF JIT in Linux allows attackers to crash affected systems through non-converging compilation. In bpf_int_jit_compile(), the exhaustion path passes a NULL jit_data->header to bpf_jit_binary_free(), which requires a non-NULL argument. The fault is limited to RISC-V kernels with the BPF JIT enabled and interrupts availability by crashing the system.

CVSS severity7.5
High
EPSS probability0.68%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

NULL pointer dereference in the RISC-V BPF JIT in Linux allows attackers to crash affected systems through non-converging compilation. In bpf_int_jit_compile(), the exhaustion path passes a NULL jit_data->header to bpf_jit_binary_free(), which requires a non-NULL argument. The fault is limited to RISC-V kernels with the BPF JIT enabled and interrupts availability by crashing the system.

The record

CVE
CVE-2021-47486
Published
May 22, 2024
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-476, T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. May 22, 2024CVE publishedPublication date reported by the CVE source.
  2. May 11, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=5.7
  2. Affected versionversion=ca6cb5447ceca6a87d6b62c9e5d41042c34f7ffa <27de809a3d83a6199664479ebb19712533d6fd9b
  3. Affected versionversion=ca6cb5447ceca6a87d6b62c9e5d41042c34f7ffa <cac6b043cea3e120f4fccec16f7381747cbfdc0d
  4. Affected versionversion=ca6cb5447ceca6a87d6b62c9e5d41042c34f7ffa <e1b80a5ebe5431caeb20f88c32d4a024777a2d41

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=5.7; version=ca6cb5447ceca6a87d6b62c9e5d41042c34f7ffa <27de809a3d83a6199664479ebb19712533d6fd9b; version=ca6cb5447ceca6a87d6b62c9e5d41042c34f7ffa <cac6b043cea3e120f4fccec16f7381747cbfdc0d; version=ca6cb5447ceca6a87d6b62c9e5d41042c34f7ffa <e1b80a5ebe5431caeb20f88c32d4a024777a2d41
The Linux Kernel Organization · Linux Kernelversion=5.7; version=ca6cb5447cec <=27de809a3d83; version=ca6cb5447cec <cac6b043cea3; version=ca6cb5447cec <e1b80a5ebe54

Published CVSS scores

5.5SUSECVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
7.5UbuntuCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-476NULL Pointer Dereference
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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