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CVE-2021-3489— Linux kernel eBPF RINGBUF map oversized allocation

Quick assessment

Affected
Linux Linux kernel
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Linux kernel是美国Linux基金会的开源操作系统Linux所使用的内核。 Linux kernel 存在缓冲区错误漏洞。该漏洞源于eBPF RINGBUF bpf_ringbuf_reserve并未检查分配的大小是否小于ringbuf大小。

CVSS 7.8 · High EPSS 0.55% · P44

Possible ATT&CK Techniques 1 AI

T1203 · Exploitation for Client Execution
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I. Basic Information for CVE-2021-3489

Vulnerability Information
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Vulnerability Title
Linux kernel eBPF RINGBUF map oversized allocation
Source: CVE Program / CVE List V5
Vulnerability Description
The eBPF RINGBUF bpf_ringbuf_reserve() function in the Linux kernel did not check that the allocated size was smaller than the ringbuf size, allowing an attacker to perform out-of-bounds writes within the kernel and therefore, arbitrary code execution. This issue was fixed via commit 4b81ccebaeee ("bpf, ringbuf: Deny reserve of buffers larger than ringbuf") (v5.13-rc4) and backported to the stable kernels in v5.12.4, v5.11.21, and v5.10.37. It was introduced via 457f44363a88 ("bpf: Implement BPF ring buffer and verifier support for it") (v5.8-rc1).
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
内存缓冲区边界内操作的限制不恰当
Source: CVE Program / CVE List V5
Vulnerability Title
Linux kernel 缓冲区错误漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Linux kernel是美国Linux基金会的开源操作系统Linux所使用的内核。 Linux kernel 存在缓冲区错误漏洞。该漏洞源于eBPF RINGBUF bpf_ringbuf_reserve并未检查分配的大小是否小于ringbuf大小。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
Linux Linux kernel trunk ~ v5.13-rc4 -

II. Public POCs for CVE-2021-3489

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III. Intelligence Information for CVE-2021-3489

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Patches & Fixes for CVE-2021-3489 (1)

Vendor Advisories for CVE-2021-3489 (4)

Mailing List Discussions for CVE-2021-3489 (1)

Same Patch Batch · Linux · 2021-06-04 · 3 CVEs total

CVE-2021-3491 7.8 HIGH Linux kernel io_uring PROVIDE_BUFFERS MAX_RW_COUNT bypass
CVE-2021-3490 7.8 HIGH Linux kernel eBPF bitwise ops ALU32 bounds tracking

IV. Related Vulnerabilities

Same product: Linux kernel
Same vendor: Linux
Same weakness: CWE-119

V. Comments for CVE-2021-3489

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