SECUFOCUSNOW
Home›CVE index›CVE-2021-47520
Review reviewHigh

CVE-2021-47520

Linux Linux, linux kernel

In the Linux kernel, the following vulnerability has been resolved: can: pch_can: pch_can_rx_normal: fix use after free After calling netif_receive_skb(skb), dereferencing skb is unsafe. Especially, the can_frame cf which aliases skb memory is dereferenced just after the call netif_receive_skb(skb). Reordering the lines solves the issue.

CVSS
7.8
EPSS
0.34%
26.4% percentile
CISA KEV
Not listed
Published
2024.05.25
PRIORITY ASSESSMENT

Review review

The CVSS severity warrants an early asset and exposure review.

Known exploitationNot established by KEV
Exploit probability0.34%
Technical severityCVSS 7.8

Vulnerability overview

In the Linux kernel, the following vulnerability has been resolved: can: pch_can: pch_can_rx_normal: fix use after free After calling netif_receive_skb(skb), dereferencing skb is unsafe. Especially, the can_frame cf which aliases skb memory is dereferenced just after the call netif_receive_skb(skb). Reordering the lines solves the issue.

Affected product and versions

Product
Linux Linux, linux kernel
Affected versions
>= b21d18b51b31a24d17f883b678432fbdee3d5675 < bafe343a885c70dddf358379cf0b2a1c07355d8d, >= b21d18b51b31a24d17f883b678432fbdee3d5675 < 3a3c46e2eff0577454860a203be1a8295f4acb76, >= b21d18b51b31a24d17f883b678432fbdee3d5675 < affbad02bf80380a7403885b9fe4a1587d1bb4f3, >= b21d18b51b31a24d17f883b678432fbdee3d5675 < 3e193ef4e0a3f5bf92ede83ef214cb09d01b00aa, >= b21d18b51b31a24d17f883b678432fbdee3d5675 < abb4eff3dcd2e583060082a18a8dbf31f02689d4, >= b21d18b51b31a24d17f883b678432fbdee3d5675 < 703dde112021c93d6e89443c070e7dbd4dea612e, >= b21d18b51b31a24d17f883b678432fbdee3d5675 < 6c73fc931658d8cbc8a1714b326cb31eb71d16a7, >= b21d18b51b31a24d17f883b678432fbdee3d5675 < 94cddf1e9227a171b27292509d59691819c458db, >= 2.6.37, >= 2.6.37 < 4.4.295, >= 4.5 < 4.9.293, >= 4.10 < 4.14.258, >= 4.15 < 4.19.221, >= 4.20 < 5.4.165, >= 5.5 < 5.10.85, >= 5.11 < 5.15.8
Fixed versions
4.4.295, 4.9.293, 4.14.258, 4.19.221, 5.4.165, 5.10.85, 5.15.8

Recommended response sequence

Confirm exposure before applying a vendor-supported change.

Full remediation guide
  1. 1
    Identify

    Confirm that Linux Linux, linux kernel and an affected version are present.

  2. 2
    Prioritize

    Combine exploitation signals with asset exposure and business criticality.

  3. 3
    Remediate

    Follow the vendor advisory or supported update path and preserve rollback options.

  4. 4
    Verify

    Recheck the version, service health, access paths, and relevant logs.

Technical data

CVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CWE
CWE-416