CVE-2026-31504: net: fix fanout UAF in packet_release() via NETDEV_UP race

Affected versions

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

• linux linux kernel3.1.1 and later · before 5.10.253
• linux linux kernel5.11 and later · before 5.15.203
• linux linux kernel5.16 and later · before 6.1.168
• linux linux kernel6.2 and later · before 6.6.131
• linux linux kernel6.7 and later · before 6.12.80
• linux linux kernel6.13 and later · before 6.18.21
• linux linux kernel6.19 and later · before 6.19.11
• linux linux kernel3.1
• linux linux kernel7.0

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

  • 3.1affected
  • ce06b03e60fc19c680d1bf873e779bf11c2fc518 and later · before ee642b1962caa9aa231c01abbd58bc453ae6b66eaffected · git
  • ce06b03e60fc19c680d1bf873e779bf11c2fc518 and later · before 42cfd7898eeed290c9fb73f732af1f7d6b0a703eaffected · git
  • ce06b03e60fc19c680d1bf873e779bf11c2fc518 and later · before 1b4c03f8892d955385c202009af7485364731bb9affected · git
  • ce06b03e60fc19c680d1bf873e779bf11c2fc518 and later · before 654386baef228c2992dbf604c819e4c7c35fc71baffected · git
  • ce06b03e60fc19c680d1bf873e779bf11c2fc518 and later · before 75fe6db23705a1d55160081f7b37db9665b1880baffected · git
  • ce06b03e60fc19c680d1bf873e779bf11c2fc518 and later · before d0c7cdc15fdf8c4f91aca1928e52295d175b6ec6affected · git
  • ce06b03e60fc19c680d1bf873e779bf11c2fc518 and later · before ceccbfc6de720ad633519a226715989cfb065af1affected · git
  • ce06b03e60fc19c680d1bf873e779bf11c2fc518 and later · before 42156f93d123436f2a27c468f18c966b7e5db796affected · git
  • before 3.1not 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-2026-31502Apr 22, 2026 · team: fix header_ops type confusion with non-Ethernet ports
  31Monitor
• ← EarlierCVE-2026-31503Apr 22, 2026 · udp: Fix wildcard bind conflict check when using hash2
  22Monitor
• Later →CVE-2026-31505Apr 22, 2026 · iavf: fix out-of-bounds writes in iavf_get_ethtool_stats()
  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.