6.8

CVE-2026-63983: linux

CVSS: 6.8v4.0MediumUndergoing analysis
AliasesUBUNTU-CVE-2026-63983DEBIAN-CVE-2026-63983
Published 19-07-2026Last modified 15-10-2026
Open JSON

Vulnerability summary

CVE-2026-63983 is a medium (CVSS 6.8) vulnerability in linux. EPSS estimates a 0.21% chance of exploitation in the next 30 days, higher than 10.4% of scored vulnerabilities.

Overall risk
27/100
0100
Medium · default modelHow is this calculated?
CVSS score
6.8/10
010
Medium · v4.0 (OSV · Ubuntu), selected by version preference
EPSS score
0.21%
0%100%
Low · +0.04 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 13 · Related 13
OPENSUSE-SU-2026:22091-1SUSE-SU-2026:24179-1SUSE-SU-2026:24184-1SUSE-SU-2026:24197-1SUSE-SU-2026:24235-1USN-8593-1

Timeline

  1. 19-07-2026
    PublishedVulnerability first disclosed.
  2. 15-10-2026
    Last modifiedVulnerability information updated.

Description

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. This marks the packet itself rather than mutating qdisc state, therefore it is safe regardless of tree topology or concurrency.

CVSS metrics

1 score · 1 source · 1 version

EPSS trend

Probability

0.21%

Chance of exploitation in the next 30 days

Percentile

10%

Versus all other CVEs

30-day change

+0.04 pp

From 0.17% on 21-09-2026

21-09-202621-10-2026
EPSS score
0.21%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

No weakness data has been published for this record.

Affected systems

Ubuntu168 products
  • linuxAll versions (No fix recorded) | < 7.0.0-28.28
  • linux-allwinner-5.19All versions (No fix recorded)
  • linux-awsAll versions (No fix recorded) | < 7.0.0-1009.9
  • linux-aws-5.0All versions (No fix recorded)
  • linux-aws-5.11All versions (No fix recorded)
Debian1 product
  • linuxAll versions (No fix recorded) | < 6.12.94-1 | < 7.0.12-1
Linux1 product
  • linux≥ 0afb51e72855971dba83b3c6b70c547c2d1161fd, < 1a298a514ce766c6d0c232991a390fec67af81ad | ≥ 0afb51e72855971dba83b3c6b70c547c2d1161fd, < 4ec3a8ca97394f17e73a4d8d4c79c1c78b322772 | ≥ 0afb51e72855971dba83b3c6b70c547c2d1161fd, < cfb2616042767ab31260d4f39190c381bec8b12e | ≥ 0afb51e72855971dba83b3c6b70c547c2d1161fd, < 9552b11e3edabc97cfcd9f29103d5afbce7ae183 | 2.6.12

3 vendors · 170 products

References

16 links
Show all 16 references