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Review reviewHigh

CVE-2021-47668

Linux Linux, linux kernel

In the Linux kernel, the following vulnerability has been resolved: can: dev: can_restart: fix use after free bug After calling netif_rx_ni(skb), dereferencing skb is unsafe. Especially, the can_frame cf which aliases skb memory is accessed after the netif_rx_ni() in: stats->rx_bytes += cf->len; Reordering the lines solves the issue.

CVSS
8.8
EPSS
-
- percentile
CISA KEV
Not listed
Published
2025.04.18
PRIORITY ASSESSMENT

Review review

The CVSS severity warrants an early asset and exposure review.

Known exploitationNot established by KEV
Exploit probability-
Technical severityCVSS 8.8

Vulnerability overview

In the Linux kernel, the following vulnerability has been resolved: can: dev: can_restart: fix use after free bug After calling netif_rx_ni(skb), dereferencing skb is unsafe. Especially, the can_frame cf which aliases skb memory is accessed after the netif_rx_ni() in: stats->rx_bytes += cf->len; Reordering the lines solves the issue.

Affected product and versions

Product
Linux Linux, linux kernel
Affected versions
>= 39549eef3587f1c1e8c65c88a2400d10fd30ea17 < 260925a0b7d2da5449f8ecfd02c1405e0c8a45b8, >= 39549eef3587f1c1e8c65c88a2400d10fd30ea17 < bbc6847b9b8978b520f62fbc7c68c54ef0f8d282, >= 39549eef3587f1c1e8c65c88a2400d10fd30ea17 < 92668d28c7e6a7a2ba07df287669ffcdf650c421, >= 39549eef3587f1c1e8c65c88a2400d10fd30ea17 < 08ab951787098ae0b6c0364aeea7a8138226f234, >= 39549eef3587f1c1e8c65c88a2400d10fd30ea17 < ac48ef15826e83f4206c47add61072e8fc76d328, >= 39549eef3587f1c1e8c65c88a2400d10fd30ea17 < 593c072b7b3c4d7044416eb039d9ad706bedd67a, >= 39549eef3587f1c1e8c65c88a2400d10fd30ea17 < 03f16c5075b22c8902d2af739969e878b0879c94, >= 2.6.31, >= 2.6.31 < 4.4.254, >= 4.5 < 4.9.254, >= 4.10 < 4.14.218, >= 4.15 < 4.19.171, >= 4.20 < 5.4.93, >= 5.5 < 5.10.11, 5.11
Fixed versions
4.4.254, 4.9.254, 4.14.218, 4.19.171, 5.4.93, 5.10.11

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