CVE-2026-90050
Received
Received - Intake
BaseFortify
Vulnerability report for CVE-2026-90050, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.
Publication date: 2026-09-17
Last updated on: 2026-09-17
Assigner: kernel.org
Description
Description
In the Linux kernel, the following vulnerability has been resolved:
net/sched: fq: clamp quantum and initial_quantum in change path
The fq change path accepts TCA_FQ_QUANTUM in [1, INT_MAX] and
TCA_FQ_INITIAL_QUANTUM up to INT_MAX, while fq_init() already clamps to
[1, 1<<20]. A user can override the init clamp via tc qdisc change,
restoring the small-quantum deficit spin that the init clamp prevents.
Narrow iq_range.max to 1<<20 so TCA_FQ_INITIAL_QUANTUM is rejected at
parse time. Clamp TCA_FQ_QUANTUM to [256, 1<<20] in fq_change() and
fq_init() quantum to [256, 1<<20] for tiny-MTU devices.
Conditions to recreate the bug:
CONFIG_NET_SCH_FQ=y. Requires CAP_NET_ADMIN (namespace-local via
unshare -Urn suffices).
tc qdisc add dev dummy0 root fq
tc qdisc change dev dummy0 root fq quantum 1 stab data 32768 size_log 15 cell_log 0
CVSS Scores
EPSS Scores
| Probability: | |
| Percentile: |
Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| Linux | Linux | d16dac3925be95ad46e986d4b139c9898b6e227f |
| Linux | Linux | f6b3e3848a5fca63438984acd6d9eceac80814c1 |
| Linux | Linux | e35acd56f244d94355f9ab237c2ecc8fba5e6f04 |
| Linux | Linux | 709f34f7c28dc4dd6c40343d101850f11e172312 |
| Linux | Linux | 7.3-rc1 |
Helpful Resources
Exploitability
CWE
KEV
| CWE ID | Description |
|---|---|
| CWE-UNKNOWN |
