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CVE-2021-47668— can: dev: can_restart: fix use after free bug

Quick assessment

Affected
Linux Linux
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存在安全漏洞，该漏洞源于在can_restart函数中释放后重用skb内存。

CVSS 8.8 · High EPSS 0.24% · P14

Possible ATT&CK Techniques 1 AI

T1068 · Exploitation for Privilege Escalation

Affected Version Matrix 16

VendorProduct Version RangeStatus
Linux Linux 39549eef3587f1c1e8c65c88a2400d10fd30ea17< 260925a0b7d2da5449f8ecfd02c1405e0c8a45b8 affected
39549eef3587f1c1e8c65c88a2400d10fd30ea17< bbc6847b9b8978b520f62fbc7c68c54ef0f8d282 affected
39549eef3587f1c1e8c65c88a2400d10fd30ea17< 92668d28c7e6a7a2ba07df287669ffcdf650c421 affected
39549eef3587f1c1e8c65c88a2400d10fd30ea17< 08ab951787098ae0b6c0364aeea7a8138226f234 affected
39549eef3587f1c1e8c65c88a2400d10fd30ea17< ac48ef15826e83f4206c47add61072e8fc76d328 affected
39549eef3587f1c1e8c65c88a2400d10fd30ea17< 593c072b7b3c4d7044416eb039d9ad706bedd67a affected
39549eef3587f1c1e8c65c88a2400d10fd30ea17< 03f16c5075b22c8902d2af739969e878b0879c94 affected
2.6.31 affected
… +8 more rows
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I. Basic Information for CVE-2021-47668

Vulnerability Information
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Vulnerability Title
can: dev: can_restart: fix use after free bug
Source: CVE Program / CVE List V5
Vulnerability Description
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.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
N/A
Source: CVE Program / CVE List V5
Vulnerability Title
Linux kernel 安全漏洞
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存在安全漏洞，该漏洞源于在can_restart函数中释放后重用skb内存。
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 39549eef3587f1c1e8c65c88a2400d10fd30ea17 ~ 260925a0b7d2da5449f8ecfd02c1405e0c8a45b8 -
Linux Linux 2.6.31 -

II. Public POCs for CVE-2021-47668

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III. Intelligence Information for CVE-2021-47668

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Other References for CVE-2021-47668 (5)

Same Patch Batch · Linux · 2025-04-17 · 5 CVEs total

CVE-2021-47670 8.8 HIGH can: peak_usb: fix use after free bugs
CVE-2021-47669 7.8 HIGH can: vxcan: vxcan_xmit: fix use after free bug
CVE-2021-47671 can: etas_es58x: es58x_rx_err_msg(): fix memory leak in error path
CVE-2020-36789 can: dev: can_get_echo_skb(): prevent call to kfree_skb() in hard IRQ context

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

V. Comments for CVE-2021-47668

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