{"schema":"threatline.record/2","record":{"id":"CVE-2026-93830","aliases":[],"summary":"net: stmmac: xgmac2: disable RBUE in default RX interrupt mask","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: stmmac: xgmac2: disable RBUE in default RX interrupt mask\n\nEnabling the RX Buffer Unavailable (RBUE) interrupt is counterproductive\nand can trigger a MAC interrupt storm under heavy RX pressure. When the\nDMA runs out of RX descriptors it fires RBUE continuously until software\nrefills the ring.\n\nHowever, RBUE is redundant: the normal RX completion interrupt (RIE)\nalready triggers NAPI, which processes completed descriptors and refills\nthe ring, causing the DMA to resume. The RBUE handler itself only sets\nhandle_rx - the same outcome as RIE.\n\nOn Agilex5 under heavy RX pressure, the MAC interrupt (which includes\nRBUE) was observed firing 1,821,811,555 times against only 2,618,627\nactual RX completions - a ~695x ratio - confirming the severity of the\nstorm.\n\nRBUE does not provide OOM recovery. If page_pool is exhausted,\nstmmac_rx_refill() cannot advance the DMA tail pointer, the DMA stays\nsuspended, and RBUE fires again on the next NAPI completion - a storm\nwith no forward progress. This patch trades that storm for a clean\nstall with the same RX outcome. Proper OOM recovery is a pre-existing\ngap outside the scope of this fix.\n\nNote: as a consequence of disabling RBUE, the rx_buf_unav_irq ethtool\ncounter will always read 0 on XGMAC2 devices. This behaviour is already\ninconsistent across DWMAC core versions.\n\nRemove RBUE from XGMAC_DMA_INT_DEFAULT_EN and XGMAC_DMA_INT_DEFAULT_RX\nto prevent the interrupt storm while keeping normal RX handling intact.","categories":["Operating systems"],"product":"Linux","vendor":"Linux","ecosystem":null,"affected_ranges":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-93830","source_modified_at":"2026-10-03T10:58:00.189Z","fetched_at":"2026-10-23T18:52:38.922436Z","product":"Linux","vendor":"Linux","versions":[{"version":"d6ddfacd95c79d43465d4a85dffb1c9beca343a9","lessThan":"8c9d57b5dc098b84631d0b3559c84c499ea2170a","status":"affected","versionType":"git"},{"version":"d6ddfacd95c79d43465d4a85dffb1c9beca343a9","lessThan":"7a10e54e42a8f73a8d731f5a281fc06bb41b9250","status":"affected","versionType":"git"},{"version":"d6ddfacd95c79d43465d4a85dffb1c9beca343a9","lessThan":"6b3b91433d5f4eae6865cdaa96f40cd67849e1f6","status":"affected","versionType":"git"},{"version":"d6ddfacd95c79d43465d4a85dffb1c9beca343a9","lessThan":"74dbb85a6a254b5fc1f265a6cd61b2ba9d9221d7","status":"affected","versionType":"git"},{"version":"d6ddfacd95c79d43465d4a85dffb1c9beca343a9","lessThan":"0b1a5d3647ce07c27a9fffefc11a8cbf7d7b25ce","status":"affected","versionType":"git"},{"version":"d6ddfacd95c79d43465d4a85dffb1c9beca343a9","lessThan":"87e2826ed2058747ddf014c082569a46bfadd96b","status":"affected","versionType":"git"},{"version":"d6ddfacd95c79d43465d4a85dffb1c9beca343a9","lessThan":"d3265c19b35d036bba327b36b5366bee76b0157c","status":"affected","versionType":"git"}],"defaultStatus":"unaffected"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-93830","source_modified_at":"2026-10-03T10:58:00.189Z","fetched_at":"2026-10-23T18:52:38.922436Z","product":"Linux","vendor":"Linux","versions":[{"version":"4.19","status":"affected"},{"version":"0","lessThan":"4.19","status":"unaffected","versionType":"semver"},{"version":"5.10.271","lessThanOrEqual":"5.10.*","status":"unaffected","versionType":"semver"},{"version":"5.15.222","lessThanOrEqual":"5.15.*","status":"unaffected","versionType":"semver"},{"version":"6.1.189","lessThanOrEqual":"6.1.*","status":"unaffected","versionType":"semver"},{"version":"6.6.158","lessThanOrEqual":"6.6.*","status":"unaffected","versionType":"semver"},{"version":"6.12.111","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.18.53","lessThanOrEqual":"6.18.*","status":"unaffected","versionType":"semver"},{"version":"7.2","lessThanOrEqual":"*","status":"unaffected","versionType":"original_commit_for_fix"}],"defaultStatus":"affected"}],"fixed_versions":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-93830","source_modified_at":"2026-10-03T10:58:00.189Z","fetched_at":"2026-10-23T18:52:38.922436Z","package":{"name":"Linux","ecosystem":null},"version":"8c9d57b5dc098b84631d0b3559c84c499ea2170a","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-93830","source_modified_at":"2026-10-03T10:58:00.189Z","fetched_at":"2026-10-23T18:52:38.922436Z","package":{"name":"Linux","ecosystem":null},"version":"7a10e54e42a8f73a8d731f5a281fc06bb41b9250","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-93830","source_modified_at":"2026-10-03T10:58:00.189Z","fetched_at":"2026-10-23T18:52:38.922436Z","package":{"name":"Linux","ecosystem":null},"version":"6b3b91433d5f4eae6865cdaa96f40cd67849e1f6","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-93830","source_modified_at":"2026-10-03T10:58:00.189Z","fetched_at":"2026-10-23T18:52:38.922436Z","package":{"name":"Linux","ecosystem":null},"version":"74dbb85a6a254b5fc1f265a6cd61b2ba9d9221d7","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-93830","source_modified_at":"2026-10-03T10:58:00.189Z","fetched_at":"2026-10-23T18:52:38.922436Z","package":{"name":"Linux","ecosystem":null},"version":"0b1a5d3647ce07c27a9fffefc11a8cbf7d7b25ce","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-93830","source_modified_at":"2026-10-03T10:58:00.189Z","fetched_at":"2026-10-23T18:52:38.922436Z","package":{"name":"Linux","ecosystem":null},"version":"87e2826ed2058747ddf014c082569a46bfadd96b","basis":"first unaffected version stated in the CVE record"}],"cvss":7.5,"severity":"High","kev":{"listed":false},"epss":{"probability":0.0049,"percentile":0.41225,"score_date":"2026-10-23"},"published_at":"2026-09-24T16:03:12.818Z","modified_at":"2026-10-03T10:58:00.189Z","provenance":[{"source":"CVE List","url":"https://www.cve.org/CVERecord?id=CVE-2026-93830","fetched_at":"2026-10-23T18:52:38.922436Z","source_modified_at":"2026-10-03T10:58:00.189Z"},{"source":"EPSS","url":"https://api.first.org/data/v1/epss?cve=CVE-2026-93830","fetched_at":"2026-10-23T18:42:43.628194Z","source_modified_at":"2026-10-23"}],"sources":["CVE List","EPSS"],"references":[{"source":"CVE List","url":"https://git.kernel.org/stable/c/8c9d57b5dc098b84631d0b3559c84c499ea2170a"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/7a10e54e42a8f73a8d731f5a281fc06bb41b9250"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/6b3b91433d5f4eae6865cdaa96f40cd67849e1f6"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/74dbb85a6a254b5fc1f265a6cd61b2ba9d9221d7"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/0b1a5d3647ce07c27a9fffefc11a8cbf7d7b25ce"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/87e2826ed2058747ddf014c082569a46bfadd96b"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/d3265c19b35d036bba327b36b5366bee76b0157c"}],"locations":[],"motoko_assessment":{"status":"requires_architecture_review","automatic_remediation":false},"cve_state":"PUBLISHED","cvss_source":"CVE List","classification":{"method":"product-first software-layer rules","rules_version":"2.1","matched_on":"product","confidence":"heuristic","reviewed":false},"change_timestamp":"2026-10-03T10:58:00.189Z","content_hash":"9e3f80022851bc79db9384a8317e6d5c4cfb1cdd0e01c230dd612ebb839d03f2"}}