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

Vulnerability from cvelistv5 – Published: 2025-02-18 14:37 – Updated: 2026-05-23 15:56
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 (v2.0.3)
CWE
Assigner
References
Impacted products
Vendor Product Version
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)
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)
Create a notification for this product.
Show details on NVD website
To clipboard 

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\"version\": \"2.0.3\", \"timestamp\": \"2025-02-18T15:38:37.163490Z\"}}}], \"problemTypes\": [{\"descriptions\": [{\"lang\": \"en\", \"type\": \"CWE\", \"cweId\": \"CWE-416\", \"description\": \"CWE-416 Use After Free\"}]}], \"providerMetadata\": {\"orgId\": \"134c704f-9b21-4f2e-91b3-4a467353bcc0\", \"shortName\": \"CISA-ADP\", \"dateUpdated\": \"2025-02-18T15:38:38.582Z\"}}], \"cna\": {\"title\": \"netem: Update sch-\u003eq.qlen before qdisc_tree_reduce_backlog()\", \"metrics\": [{\"cvssV3_1\": {\"version\": \"3.1\", \"baseScore\": 7.8, \"baseSeverity\": \"HIGH\", \"vectorString\": \"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H\"}}], \"affected\": [{\"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\", \"vendor\": \"Linux\", \"product\": \"Linux\", \"versions\": [{\"status\": \"affected\", \"version\": \"83c6ab12f08dcc09d4c5ac86fdb89736b28f1d31\", \"lessThan\": \"e395fec75ac2dbffc99b4bce57b7f1f3c5449f2c\", \"versionType\": \"git\"}, {\"status\": \"affected\", \"version\": \"216509dda290f6db92c816dd54b83c1df9da9e76\", \"lessThan\": \"7f31d74fcc556a9166b1bb20515542de7bb939d1\", \"versionType\": \"git\"}, {\"status\": \"affected\", \"version\": \"c2047b0e216c8edce227d7c42f99ac2877dad0e4\", \"lessThan\": \"98a2c685293aae122f688cde11d9334dddc5d207\", \"versionType\": \"git\"}, {\"status\": \"affected\", \"version\": \"10df49cfca73dfbbdb6c4150d859f7e8926ae427\", \"lessThan\": \"7b79ca9a1de6a428d486ff52fb3d602321c08f55\", \"versionType\": \"git\"}, {\"status\": \"affected\", \"version\": \"3824c5fad18eeb7abe0c4fc966f29959552dca3e\", \"lessThan\": \"1f8e3f4a4b8b90ad274dfbc66fc7d55cb582f4d5\", \"versionType\": \"git\"}, {\"status\": \"affected\", \"version\": \"356078a5c55ec8d2061fcc009fb8599f5b0527f9\", \"lessThan\": \"6312555249082d6d8cc5321ff725df05482d8b83\", \"versionType\": \"git\"}, {\"status\": \"affected\", \"version\": \"f8d4bc455047cf3903cd6f85f49978987dbb3027\", \"lessThan\": \"839ecc583fa00fab785fde1c85a326743657fd32\", \"versionType\": \"git\"}, {\"status\": \"affected\", \"version\": \"f8d4bc455047cf3903cd6f85f49978987dbb3027\", \"lessThan\": \"638ba5089324796c2ee49af10427459c2de35f71\", \"versionType\": \"git\"}], \"programFiles\": [\"net/sched/sch_netem.c\"], \"defaultStatus\": \"unaffected\"}, {\"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\", \"vendor\": \"Linux\", \"product\": \"Linux\", \"versions\": [{\"status\": \"affected\", \"version\": \"6.13\"}, {\"status\": \"unaffected\", \"version\": \"0\", \"lessThan\": \"6.13\", \"versionType\": \"semver\"}, {\"status\": \"unaffected\", \"version\": \"5.4.291\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"5.4.*\"}, {\"status\": \"unaffected\", \"version\": \"5.10.235\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"5.10.*\"}, {\"status\": \"unaffected\", \"version\": \"5.15.179\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"5.15.*\"}, {\"status\": \"unaffected\", \"version\": \"6.1.129\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"6.1.*\"}, {\"status\": \"unaffected\", \"version\": \"6.6.78\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"6.6.*\"}, {\"status\": \"unaffected\", \"version\": \"6.12.14\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"6.12.*\"}, {\"status\": \"unaffected\", \"version\": \"6.13.3\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"6.13.*\"}, {\"status\": \"unaffected\", \"version\": \"6.14\", \"versionType\": \"original_commit_for_fix\", \"lessThanOrEqual\": \"*\"}], \"programFiles\": [\"net/sched/sch_netem.c\"], \"defaultStatus\": \"affected\"}], \"references\": [{\"url\": \"https://git.kernel.org/stable/c/e395fec75ac2dbffc99b4bce57b7f1f3c5449f2c\"}, {\"url\": \"https://git.kernel.org/stable/c/7f31d74fcc556a9166b1bb20515542de7bb939d1\"}, {\"url\": \"https://git.kernel.org/stable/c/98a2c685293aae122f688cde11d9334dddc5d207\"}, {\"url\": \"https://git.kernel.org/stable/c/7b79ca9a1de6a428d486ff52fb3d602321c08f55\"}, {\"url\": \"https://git.kernel.org/stable/c/1f8e3f4a4b8b90ad274dfbc66fc7d55cb582f4d5\"}, {\"url\": \"https://git.kernel.org/stable/c/6312555249082d6d8cc5321ff725df05482d8b83\"}, {\"url\": \"https://git.kernel.org/stable/c/839ecc583fa00fab785fde1c85a326743657fd32\"}, {\"url\": \"https://git.kernel.org/stable/c/638ba5089324796c2ee49af10427459c2de35f71\"}], \"x_generator\": {\"engine\": \"bippy-1.2.0\"}, \"descriptions\": [{\"lang\": \"en\", \"value\": \"In the Linux kernel, the following vulnerability has been resolved:\\n\\nnetem: Update sch-\u003eq.qlen before qdisc_tree_reduce_backlog()\\n\\nqdisc_tree_reduce_backlog() notifies parent qdisc only if child\\nqdisc becomes empty, therefore we need to reduce the backlog of the\\nchild qdisc before calling it. 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\": \"2026-05-11T21:04:46.457Z\"}}}",
      "cveMetadata": "{\"cveId\": \"CVE-2025-21703\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2026-05-11T21:04:46.457Z\", \"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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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.