CVE-2025-37797 (GCVE-0-2025-37797)

Vulnerability from cvelistv5 – Published: 2025-05-02 14:16 – Updated: 2026-06-11 18:44
VLAI
Title
net_sched: hfsc: Fix a UAF vulnerability in class handling
Summary
In the Linux kernel, the following vulnerability has been resolved: net_sched: hfsc: Fix a UAF vulnerability in class handling This patch fixes a Use-After-Free vulnerability in the HFSC qdisc class handling. The issue occurs due to a time-of-check/time-of-use condition in hfsc_change_class() when working with certain child qdiscs like netem or codel. The vulnerability works as follows: 1. hfsc_change_class() checks if a class has packets (q.qlen != 0) 2. It then calls qdisc_peek_len(), which for certain qdiscs (e.g., codel, netem) might drop packets and empty the queue 3. The code continues assuming the queue is still non-empty, adding the class to vttree 4. This breaks HFSC scheduler assumptions that only non-empty classes are in vttree 5. Later, when the class is destroyed, this can lead to a Use-After-Free The fix adds a second queue length check after qdisc_peek_len() to verify the queue wasn't emptied.
Severity
No CVSS data available.
SSVC
Exploitation: none Automatable: no Technical Impact: total
CISA Coordinator (v2.0.3)
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: 21f4d5cc25ec0e6e8eb8420dd2c399e6d2fc7d14 , < 28b09a067831f7317c3841812276022d6c940677 (git)
Affected: 21f4d5cc25ec0e6e8eb8420dd2c399e6d2fc7d14 , < 39b9095dd3b55d9b2743df038c32138efa34a9de (git)
Affected: 21f4d5cc25ec0e6e8eb8420dd2c399e6d2fc7d14 , < fcc8ede663569c704fb00a702973bd6c00373283 (git)
Affected: 21f4d5cc25ec0e6e8eb8420dd2c399e6d2fc7d14 , < 20d584a33e480ae80d105f43e0e7b56784da41b9 (git)
Affected: 21f4d5cc25ec0e6e8eb8420dd2c399e6d2fc7d14 , < 3aa852e3605000d5c47035c3fc3a986d14ccfa9f (git)
Affected: 21f4d5cc25ec0e6e8eb8420dd2c399e6d2fc7d14 , < 86cd4641c713455a4f1c8e54c370c598c2b1cee0 (git)
Affected: 21f4d5cc25ec0e6e8eb8420dd2c399e6d2fc7d14 , < bb583c88d23b72d8d16453d24856c99bd93dadf5 (git)
Affected: 21f4d5cc25ec0e6e8eb8420dd2c399e6d2fc7d14 , < 3df275ef0a6ae181e8428a6589ef5d5231e58b5c (git)
Create a notification for this product.
Linux Linux Affected: 4.14
Unaffected: 0 , < 4.14 (semver)
Unaffected: 5.4.293 , ≤ 5.4.* (semver)
Unaffected: 5.10.237 , ≤ 5.10.* (semver)
Unaffected: 5.15.181 , ≤ 5.15.* (semver)
Unaffected: 6.1.136 , ≤ 6.1.* (semver)
Unaffected: 6.6.89 , ≤ 6.6.* (semver)
Unaffected: 6.12.26 , ≤ 6.12.* (semver)
Unaffected: 6.14.5 , ≤ 6.14.* (semver)
Unaffected: 6.15 , ≤ * (original_commit_for_fix)
Create a notification for this product.
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Later, when the class is destroyed, this can lead to a Use-After-Free\\n\\nThe fix adds a second queue length check after qdisc_peek_len() to verify\\nthe queue wasn\u0027t emptied.\"}], \"cpeApplicability\": [{\"nodes\": [{\"negate\": false, \"cpeMatch\": [{\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"5.4.293\", \"versionStartIncluding\": \"4.14\"}, {\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"5.10.237\", \"versionStartIncluding\": \"4.14\"}, {\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"5.15.181\", \"versionStartIncluding\": \"4.14\"}, {\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"6.1.136\", \"versionStartIncluding\": \"4.14\"}, {\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"6.6.89\", \"versionStartIncluding\": \"4.14\"}, {\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"6.12.26\", \"versionStartIncluding\": \"4.14\"}, {\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"6.14.5\", \"versionStartIncluding\": \"4.14\"}, {\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"6.15\", \"versionStartIncluding\": \"4.14\"}], \"operator\": \"OR\"}]}], \"providerMetadata\": {\"orgId\": \"416baaa9-dc9f-4396-8d5f-8c081fb06d67\", \"shortName\": \"Linux\", \"dateUpdated\": \"2026-05-11T21:15:20.823Z\"}}}",
      "cveMetadata": "{\"cveId\": \"CVE-2025-37797\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2026-06-11T18:44:02.667Z\", \"dateReserved\": \"2025-04-16T04:51:23.941Z\", \"assignerOrgId\": \"416baaa9-dc9f-4396-8d5f-8c081fb06d67\", \"datePublished\": \"2025-05-02T14:16:01.905Z\", \"assignerShortName\": \"Linux\"}",
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}


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Taxonomy of the tags.





Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.