CVE-2021-47240: linux kernel Out-of-bounds Read — Fix

Description

In the Linux kernel, the following vulnerability has been resolved: net: qrtr: fix OOB Read in qrtr_endpoint_post Syzbot reported slab-out-of-bounds Read in qrtr_endpoint_post. The problem was in wrong _size_ type: if (len != ALIGN(size, 4) + hdrlen) goto err; If size from qrtr_hdr is 4294967293 (0xfffffffd), the result of ALIGN(size, 4) will be 0. In case of len == hdrlen and size == 4294967293 in header this check won't fail and skb_put_data(skb, data + hdrlen, size); will read out of bound from data, which is hdrlen allocated block.

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CVSS v3.1 Score

7.1

HIGH

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H

Weakness Type (CWE)

CWE-125 Out-of-bounds Read

Affected Products

Vendor	Product	Versions
linux	linux_kernel	4.15 — 4.19.196
linux	linux_kernel	4.20 — 5.4.128
linux	linux_kernel	5.5 — 5.10.46
linux	linux_kernel	5.11 — 5.12.13
linux	linux_kernel	All
linux	linux_kernel	All
linux	linux_kernel	All
linux	linux_kernel	All
linux	linux_kernel	All
linux	linux_kernel	All

References

Advisories & Patches

Frequently Asked Questions

What is CVE-2021-47240? +

In the Linux kernel, the following vulnerability has been resolved: net: qrtr: fix OOB Read in qrtr_endpoint_post Syzbot reported slab-out-of-bounds Read in qrtr_endpoint_post. The problem was in wrong _size_ type: if (len != ALIGN(size, 4) + hdrlen) goto err; If size from qrtr_hdr is 4294967293 (0xfffffffd), the result of ALIGN(size, 4) will be 0. In case of len == hdrlen and size == 4294967293 in header this check won't fail and skb_put_data(skb, data + hdrlen, size); will read out of bound from data, which is hdrlen allocated block. It has a CVSS v3.1 base score of 7.1 (HIGH).

How severe is CVE-2021-47240? +

CVE-2021-47240 has a CVSS v3.1 score of 7.1 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching.

What products are affected by CVE-2021-47240? +

CVE-2021-47240 affects products from linux, specifically: linux_kernel. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2021-47240? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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