CVE-2026-63983
In the Linux kernel, the following vulnerability has been resolved:
net/sched: fix packet loop on netem when duplicate is on
When netem duplicates a packet it re-enqueues the copy at the root qdisc. If another netem sits in the tree the copy can be duplicated again, recursing until the stack or memory is exhausted.
The original duplication guard temporarily zeroed q->duplicate around the re-enqueue, but that does not cover all cases because it is per-qdisc state shared across all concurrent enqueue paths and is not safe without additional locking.
Use the skb tc_depth field introduced in an earlier patch: - increment it on the duplicate before re-enqueue - skip duplication for any skb whose tc_depth is already non-zero.
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This marks the packet itself rather than mutating qdisc state, therefore it is safe regardless of tree topology or concurrency.
CVSS
NVD no ha asignado puntuación CVSS a esta CVE (habitual desde el cambio de política de abril de 2026).
Probabilidad de explotación (EPSS)
- Probabilidad de explotación en los próximos 30 días: 0.21%
- Percentil entre todas las CVEs puntuadas: 10
- Fecha de la puntuación: 6/10/2026
EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).
Tecnologías afectadas (1)
⚠ Inferidas por IA a partir de la descripción — NVD aún no ha analizado esta CVE; no son CPE verificados.
Referencias
JSON original (NVD)
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{
"id": "CVE-2026-63983",
"cveTags": [],
"metrics": {},
"affected": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"affectedData": [
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"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
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{
"status": "affected",
"version": "0afb51e72855971dba83b3c6b70c547c2d1161fd",
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"programFiles": [
"net/sched/sch_netem.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
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{
"status": "affected",
"version": "2.6.12"
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{
"status": "unaffected",
"version": "0",
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"versionType": "semver"
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{
"status": "unaffected",
"version": "6.12.93",
"versionType": "semver",
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{
"status": "unaffected",
"version": "7.0.12",
"versionType": "semver",
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{
"status": "unaffected",
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],
"published": "2026-07-19T16:17:17.490",
"references": [
{
"url": "https://git.kernel.org/stable/c/1a298a514ce766c6d0c232991a390fec67af81ad",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
],
"vulnStatus": "Awaiting Analysis",
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: fix packet loop on netem when duplicate is on\n\nWhen netem duplicates a packet it re-enqueues the copy at the root qdisc.\nIf another netem sits in the tree the copy can be duplicated\nagain, recursing until the stack or memory is exhausted.\n\nThe original duplication guard temporarily zeroed q->duplicate around\nthe re-enqueue, but that does not cover all cases because it is\nper-qdisc state shared across all concurrent enqueue paths\nand is not safe without additional locking.\n\nUse the skb tc_depth field introduced in an earlier patch:\n - increment it on the duplicate before re-enqueue\n - skip duplication for any skb whose tc_depth is already non-zero.\n\nThis marks the packet itself rather than mutating qdisc state,\ntherefore it is safe regardless of tree topology or concurrency."
}
],
"lastModified": "2026-07-30T14:51:11.223",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}