{
  "cveId": "CVE-2026-98427",
  "url": "https://patchblox.com/security/cve/CVE-2026-98427",
  "summary": "CVE-2026-98427 is fixed in linux on 1 platform by DEBIAN-CVE-2026-98427 (version 7.2.8-1), released October 16, 2026. It is not reported as exploited. Patch Radar priority: Routine.",
  "title": "net/sched: codel: bound the dropping loop per dequeue call",
  "description": "In the Linux kernel, the following vulnerability has been resolved:  net/sched: codel: bound the dropping loop per dequeue call  The CoDel control law schedules the next drop one interval/sqrt(count) after the previous drop, using the configured interval (codel_params.interval). For very small intervals the scheduled step rounds down to zero, so the dropping loop in codel_dequeue() never advances and drains the entire backlog under the qdisc lock in one call - an unprivileged user can trigger a soft lockup this way.  Fix in the shared codel code used by both codel and fq_codel:  1. Make the control-law step at least 1 tick so the dropping loop    always moves forward.  2. Cap the dropping loop at CODEL_MAX_DROPS_PER_DEQUEUE (256) drops    per codel_dequeue() call, resyncing drop_next to now when the cap    is hit: the catch-up owed to the loop grows with the idle gap and    the backlog, which no interval threshold can bound. This is a    deliberate behaviour change after long idle gaps.  The cap applies to fq_codel (4b549a2ef4be) and the mac80211 TXQ path (fixed interval, cap only).  The target sojourn delay (codel_params.target) is not validated: it does not feed the control law, so a sub-tick value is aggressive rather than deadlock-prone.  Conditions to recreate the bug:   - tc qdisc add dev lo root handle 1: tbf rate 1kbit burst 2kb limit 1000000   - tc qdisc add dev lo parent 1:1 handle 10: codel interval 2us target 1ms noecn limit 1000000 (same for fq_codel)   - unpatched kernel: tc accepts it; a UDP flood under the 1kbit tbf     soft-lockups (watchdog: BUG: soft lockup) while one     codel_dequeue() call drops the backlog under the qdisc lock   - patched kernel: same setup, at most 256 drops per dequeue call,     no soft lockup  Testing: claim reproducer and interval 2us/3us variants run clean; tdc qdisc category passes (see the selftests patch).",
  "published": "2026-10-14T14:17:54Z",
  "severity": "Moderate",
  "cvss": 5.5,
  "epss": 0.00198,
  "epssPercentile": 0.09618,
  "priority": "Routine",
  "priorityTier": 4,
  "exploited": false,
  "vendorExploited": false,
  "disclosed": false,
  "vendorAdvisory": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-98427",
  "fixes": [
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 14",
      "fixedVersion": "7.2.8-1",
      "fix": "DEBIAN-CVE-2026-98427",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-98427",
      "released": "2026-10-16T15:52:00Z"
    }
  ],
  "noFixYet": [],
  "dataAsOf": "2026-11-09T01:18:40Z",
  "attribution": {
    "text": "Data: Patchblox Patch Radar",
    "url": "https://patchblox.com/security/patch-radar",
    "terms": "https://patchblox.com/security/patch-radar/use-the-data"
  }
}