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CVE-2025-21703 (GCVE-0-2025-21703)

Vulnerability from cvelistv5 – Published: 2025-02-18 14:37 – Updated: 2026-08-05 11:53
VLAI
Title
netem: Update sch->q.qlen before qdisc_tree_reduce_backlog()
Summary
In the Linux kernel, the following vulnerability has been resolved: netem: Update sch->q.qlen before qdisc_tree_reduce_backlog() qdisc_tree_reduce_backlog() notifies parent qdisc only if child qdisc becomes empty, therefore we need to reduce the backlog of the child qdisc before calling it. Otherwise it would miss the opportunity to call cops->qlen_notify(), in the case of DRR, it resulted in UAF since DRR uses ->qlen_notify() to maintain its active list.
Severity
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
SSVC
Exploitation: none Automatable: no Technical Impact: total
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2025-02-18 15:38 UTC
CWE
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 83c6ab12f08dcc09d4c5ac86fdb89736b28f1d31 , < e395fec75ac2dbffc99b4bce57b7f1f3c5449f2c (git)
Affected: 216509dda290f6db92c816dd54b83c1df9da9e76 , < 7f31d74fcc556a9166b1bb20515542de7bb939d1 (git)
Affected: c2047b0e216c8edce227d7c42f99ac2877dad0e4 , < 98a2c685293aae122f688cde11d9334dddc5d207 (git)
Affected: 10df49cfca73dfbbdb6c4150d859f7e8926ae427 , < 7b79ca9a1de6a428d486ff52fb3d602321c08f55 (git)
Affected: 3824c5fad18eeb7abe0c4fc966f29959552dca3e , < 1f8e3f4a4b8b90ad274dfbc66fc7d55cb582f4d5 (git)
Affected: 356078a5c55ec8d2061fcc009fb8599f5b0527f9 , < 6312555249082d6d8cc5321ff725df05482d8b83 (git)
Affected: f8d4bc455047cf3903cd6f85f49978987dbb3027 , < 839ecc583fa00fab785fde1c85a326743657fd32 (git)
Affected: f8d4bc455047cf3903cd6f85f49978987dbb3027 , < 638ba5089324796c2ee49af10427459c2de35f71 (git)
Affected: 5.4.288 , < 5.4.291 (semver)
Affected: 5.10.232 , < 5.10.235 (semver)
Affected: 5.15.175 , < 5.15.179 (semver)
Affected: 6.1.121 , < 6.1.129 (semver)
Affected: 6.6.67 , < 6.6.78 (semver)
Affected: 6.12.6 , < 6.12.14 (semver)
guessed Create a notification for this product.
Linux Linux Affected: 6.13
Unaffected: 0 , < 6.13 (semver)
Unaffected: 5.4.291 , ≤ 5.4.* (semver)
Unaffected: 5.10.235 , ≤ 5.10.* (semver)
Unaffected: 5.15.179 , ≤ 5.15.* (semver)
Unaffected: 6.1.129 , ≤ 6.1.* (semver)
Unaffected: 6.6.78 , ≤ 6.6.* (semver)
Unaffected: 6.12.14 , ≤ 6.12.* (semver)
Unaffected: 6.13.3 , ≤ 6.13.* (semver)
Unaffected: 6.14 , ≤ * (original_commit_for_fix)
guessed Create a notification for this product.
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Tags
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.


Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.