CVE-2021-47240: net: qrtr: fix OOB Read in qrtr_endpoint_post

Severity: high (CVSS 7.1 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2024-05-21 · updated 2026-08-04
Weakness: CWE-125

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.

Affected products

Linux kernel: from 4.15 before 4.19.196; from 4.20 before 5.4.128; from 5.5 before 5.10.46; from 5.11 before 5.12.13; 5.13-rc1, 5.13-rc2, 5.13-rc3, 5.13-rc4, 5.13-rc5, 5.13-rc6 — fixed in 4.19.196, 5.10.46, 5.12.13, 5.4.128

How to fix

Upgrade to a fixed version: Linux kernel 4.19.196, 5.10.46, 5.12.13, 5.4.128. Check the vendor advisory for mitigations.

References

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