{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-90050","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2026-09-11T19:38:34.783Z","datePublished":"2026-09-17T16:05:36.970Z","dateUpdated":"2026-09-17T16:05:36.970Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-09-17T16:05:36.970Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: fq: clamp quantum and initial_quantum in change path\n\nThe fq change path accepts TCA_FQ_QUANTUM in [1, INT_MAX] and\nTCA_FQ_INITIAL_QUANTUM up to INT_MAX, while fq_init() already clamps to\n[1, 1<<20]. A user can override the init clamp via tc qdisc change,\nrestoring the small-quantum deficit spin that the init clamp prevents.\n\nNarrow iq_range.max to 1<<20 so TCA_FQ_INITIAL_QUANTUM is rejected at\nparse time. Clamp TCA_FQ_QUANTUM to [256, 1<<20] in fq_change() and\nfq_init() quantum to [256, 1<<20] for tiny-MTU devices.\n\nConditions to recreate the bug:\n  CONFIG_NET_SCH_FQ=y. Requires CAP_NET_ADMIN (namespace-local via\n  unshare -Urn suffices).\n\n  tc qdisc add dev dummy0 root fq\n  tc qdisc change dev dummy0 root fq quantum 1 stab data 32768 size_log 15 cell_log 0"}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/sched/sch_fq.c"],"versions":[{"version":"d16dac3925be95ad46e986d4b139c9898b6e227f","lessThan":"a27498d34c3f429fb6db3aa609569f8154afa175","status":"affected","versionType":"git"},{"version":"f6b3e3848a5fca63438984acd6d9eceac80814c1","lessThan":"798283cd0fe7ba997f67e5a917f14ab40afa8d9f","status":"affected","versionType":"git"},{"version":"e35acd56f244d94355f9ab237c2ecc8fba5e6f04","lessThan":"72e9387884554f47b03bfd40fb8b2bf52789c68d","status":"affected","versionType":"git"},{"version":"709f34f7c28dc4dd6c40343d101850f11e172312","lessThan":"094cc07f98dfe70a34e2a1923af17fd29b8cf622","status":"affected","versionType":"git"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/sched/sch_fq.c"],"versions":[{"version":"7.3-rc1","status":"affected"},{"version":"0","lessThan":"7.3-rc1","status":"unaffected","versionType":"semver"},{"version":"7.3-rc3","lessThanOrEqual":"*","status":"unaffected","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"7.3-rc1","versionEndExcluding":"7.3-rc3"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/a27498d34c3f429fb6db3aa609569f8154afa175"},{"url":"https://git.kernel.org/stable/c/798283cd0fe7ba997f67e5a917f14ab40afa8d9f"},{"url":"https://git.kernel.org/stable/c/72e9387884554f47b03bfd40fb8b2bf52789c68d"},{"url":"https://git.kernel.org/stable/c/094cc07f98dfe70a34e2a1923af17fd29b8cf622"}],"title":"net/sched: fq: clamp quantum and initial_quantum in change path","x_generator":{"engine":"bippy-1.2.0"}}}}