CVE-2025-37797: net_sched: hfsc: Fix a UAF vulnerability in class handling

Affected versions

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

• debian debian linux11.0
• linux linux kernel5.5 and later · before 5.10.237
• linux linux kernel5.11 and later · before 5.15.181
• linux linux kernel5.16 and later · before 6.1.136
• linux linux kernel6.2 and later · before 6.6.89
• linux linux kernel4.14.1 and later · before 5.4.293
• linux linux kernel6.13 and later · before 6.14.5
• linux linux kernel6.7 and later · before 6.12.26
• linux linux kernel4.14
• linux linux kernel6.15

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

  • 4.14affected
  • 21f4d5cc25ec0e6e8eb8420dd2c399e6d2fc7d14 and later · before 28b09a067831f7317c3841812276022d6c940677affected · git
  • 21f4d5cc25ec0e6e8eb8420dd2c399e6d2fc7d14 and later · before 39b9095dd3b55d9b2743df038c32138efa34a9deaffected · git
  • 21f4d5cc25ec0e6e8eb8420dd2c399e6d2fc7d14 and later · before fcc8ede663569c704fb00a702973bd6c00373283affected · git
  • 21f4d5cc25ec0e6e8eb8420dd2c399e6d2fc7d14 and later · before 20d584a33e480ae80d105f43e0e7b56784da41b9affected · git
  • 21f4d5cc25ec0e6e8eb8420dd2c399e6d2fc7d14 and later · before 3aa852e3605000d5c47035c3fc3a986d14ccfa9faffected · git
  • 21f4d5cc25ec0e6e8eb8420dd2c399e6d2fc7d14 and later · before 86cd4641c713455a4f1c8e54c370c598c2b1cee0affected · git
  • 21f4d5cc25ec0e6e8eb8420dd2c399e6d2fc7d14 and later · before bb583c88d23b72d8d16453d24856c99bd93dadf5affected · git
  • 21f4d5cc25ec0e6e8eb8420dd2c399e6d2fc7d14 and later · before 3df275ef0a6ae181e8428a6589ef5d5231e58b5caffected · git
  • before 4.14not 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-2022-49892May 1, 2025 · ftrace: Fix use-after-free for dynamic ftrace_ops
  31Monitor
• ← EarlierCVE-2022-49905May 1, 2025 · net/smc: Fix possible leaked pernet namespace in smc_init()
  22Monitor
• Later →CVE-2022-49932May 2, 2025 · KVM: VMX: Do _all_ initialization before exposing /dev/kvm to userspace
  22Monitor

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.