CVE-2026-90050
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
Affected versions
Linux kernel versions
7.3-rc1
and later are affected. Fixed in
7.3-rc3
and their respective stable series.
References
4 totalFrequently asked questions
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What is CVE-2026-90050?
CVE-2026-90050 is a unscored severity Linux kernel vulnerability . It affects Linux kernel versions from 7.3-rc1 onward and has been patched in 7.3-rc3. CVE-2026-90050 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
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Is there a patch available for CVE-2026-90050?
Yes. CVE-2026-90050 has been patched. Fixed versions include 7.3-rc3. If you are running Linux kernel 7.3-rc1 or later up to the fix versions, apply the relevant patch for your kernel branch.
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Is CVE-2026-90050 actively exploited?
No. CVE-2026-90050 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.