CVE-2025-21703 (GCVE-0-2025-21703)
Vulnerability from cvelistv5 – Published: 2025-02-18 14:37 – Updated: 2026-08-05 11:53
VLAI
EPSS
VEX
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)
SSVC
Exploitation: none
Automatable: no
Technical Impact: total
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2025-02-18 15:38 UTC
CWE
- CWE-416 - Use After Free
Assigner
References
9 references
Impacted products
2 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 | |
| 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 |
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De lo contrario, perder\u00eda la oportunidad de llamar a cops-\u0026gt;qlen_notify(), en el caso de DRR, result\u00f3 en UAF ya que DRR usa -\u0026gt;qlen_notify() para mantener su lista 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"redhat_vex": {
"aggregate_severity": "Moderate",
"current_release_date": "2026-06-29T23:55:30+00:00",
"cve": "CVE-2025-21703",
"id": "CVE-2025-21703",
"initial_release_date": "2025-02-18T00:00:00+00:00",
"product_status:known_affected": "14",
"product_status:known_not_affected": "260",
"source": "Red Hat CSAF VEX",
"status": "final",
"title": "kernel: netem: Update sch-\u003eq.qlen before qdisc_tree_reduce_backlog()",
"url": "https://security.access.redhat.com/data/csaf/v2/vex/2025/cve-2025-21703.json",
"version": "3"
},
"suse_vex": {
"aggregate_severity": "important",
"current_release_date": "2026-09-12T16:53:08Z",
"cve": "CVE-2025-21703",
"id": "CVE-2025-21703",
"initial_release_date": "2025-02-19T00:15:48Z",
"product_status:known_affected": "344",
"product_status:known_not_affected": "230",
"product_status:recommended": "709",
"source": "SUSE CSAF VEX",
"status": "interim",
"title": "SUSE CVE CVE-2025-21703",
"url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2025-21703.json",
"version": "63"
},
"vulnrichment": {
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Otherwise it would miss the opportunity\\nto call cops-\u003eqlen_notify(), in the case of DRR, it resulted in UAF\\nsince DRR uses -\u003eqlen_notify() to maintain its active list.\"}], \"cpeApplicability\": [{\"nodes\": [{\"negate\": false, \"cpeMatch\": [{\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"5.4.291\", \"versionStartIncluding\": \"5.4.288\"}, {\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"5.10.235\", \"versionStartIncluding\": \"5.10.232\"}, {\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"5.15.179\", \"versionStartIncluding\": \"5.15.175\"}, {\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"6.1.129\", \"versionStartIncluding\": \"6.1.121\"}, {\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"6.6.78\", \"versionStartIncluding\": \"6.6.67\"}, {\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"6.12.14\", \"versionStartIncluding\": \"6.12.6\"}, {\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"6.13.3\", \"versionStartIncluding\": \"6.13\"}, {\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"6.14\", \"versionStartIncluding\": \"6.13\"}], \"operator\": \"OR\"}]}], \"providerMetadata\": {\"orgId\": \"416baaa9-dc9f-4396-8d5f-8c081fb06d67\", \"shortName\": \"Linux\", \"dateUpdated\": \"2026-08-05T11:53:46.285Z\"}}}",
"cveMetadata": "{\"cveId\": \"CVE-2025-21703\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2026-08-05T11:53:46.285Z\", \"dateReserved\": \"2024-12-29T08:45:45.751Z\", \"assignerOrgId\": \"416baaa9-dc9f-4396-8d5f-8c081fb06d67\", \"datePublished\": \"2025-02-18T14:37:44.261Z\", \"assignerShortName\": \"Linux\"}",
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
}
}
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Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
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.
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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
model, served locally by ML-Gateway.
They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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