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

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

• linux linux kernel2.6.31 and later · before 4.4.254
• linux linux kernel4.5 and later · before 4.9.254
• linux linux kernel4.10 and later · before 4.14.218
• linux linux kernel4.15 and later · before 4.19.171
• linux linux kernel4.20 and later · before 5.4.93
• linux linux kernel5.5 and later · before 5.10.11
• linux linux kernel5.11

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

• Linux Linux

  • 2.6.31affected
  • 39549eef3587f1c1e8c65c88a2400d10fd30ea17 and later · before 260925a0b7d2da5449f8ecfd02c1405e0c8a45b8affected · git
  • 39549eef3587f1c1e8c65c88a2400d10fd30ea17 and later · before bbc6847b9b8978b520f62fbc7c68c54ef0f8d282affected · git
  • 39549eef3587f1c1e8c65c88a2400d10fd30ea17 and later · before 92668d28c7e6a7a2ba07df287669ffcdf650c421affected · git
  • 39549eef3587f1c1e8c65c88a2400d10fd30ea17 and later · before 08ab951787098ae0b6c0364aeea7a8138226f234affected · git
  • 39549eef3587f1c1e8c65c88a2400d10fd30ea17 and later · before ac48ef15826e83f4206c47add61072e8fc76d328affected · git
  • 39549eef3587f1c1e8c65c88a2400d10fd30ea17 and later · before 593c072b7b3c4d7044416eb039d9ad706bedd67aaffected · git
  • 39549eef3587f1c1e8c65c88a2400d10fd30ea17 and later · before 03f16c5075b22c8902d2af739969e878b0879c94affected · git
  • before 2.6.31not affected · semver
  • 4.4.254 and later · up to and including 4.4.*not affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

Other highest-scoring records for the same primary product.

• CVE-2026-31431crypto: algif_aead - Revert to operating out-of-placeKEV
  90Now
• CVE-2022-0847A flaw was found in the way the "flags" member of the new pipe buffer structure was lacking proper initialization in copy_page_to_iter_pipe KEV
  89Now
• CVE-2021-22555Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACEKEV
  85Now

Published before and after this one in the same product

• ← EarlierCVE-2025-2073Apr 16, 2025 · Out-of-Bounds Read in netfilter/ipset in Linux Kernel ChromeOS [6.1, 5.15, 5.10, 5.4, 4.19] allows a local attacker with low privileges to t
  35Monitor
• ← EarlierCVE-2020-36789Apr 17, 2025 · can: dev: can_get_echo_skb(): prevent call to kfree_skb() in hard IRQ context
  22Monitor
• Later →CVE-2021-47669Apr 17, 2025 · can: vxcan: vxcan_xmit: fix use after free bug
  31Monitor

Root cause

After a memory region is freed, another reference pointing to it is still used. By then, the same region may have been allocated for different data.

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

1free(dev->buf);2/* ... another thread is still running ... */3process(dev->buf);

1lock(&dev->lock);2free(dev->buf);3dev->buf = NULL;4unlock(&dev->lock);

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.