{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-46110","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2026-05-13T15:03:33.098Z","datePublished":"2026-05-28T09:35:18.359Z","dateUpdated":"2026-06-19T11:59:33.692Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-06-19T11:59:33.692Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: stmmac: Prevent NULL deref when RX memory exhausted\n\nThe CPU receives frames from the MAC through conventional DMA: the CPU\nallocates buffers for the MAC, then the MAC fills them and returns\nownership to the CPU. For each hardware RX queue, the CPU and MAC\ncoordinate through a shared ring array of DMA descriptors: one\ndescriptor per DMA buffer. Each descriptor includes the buffer's\nphysical address and a status flag (\"OWN\") indicating which side owns\nthe buffer: OWN=0 for CPU, OWN=1 for MAC. The CPU is only allowed to set\nthe flag and the MAC is only allowed to clear it, and both must move\nthrough the ring in sequence: thus the ring is used for both\n\"submissions\" and \"completions.\"\n\nIn the stmmac driver, stmmac_rx() bookmarks its position in the ring\nwith the `cur_rx` index. The main receive loop in that function checks\nfor rx_descs[cur_rx].own=0, gives the corresponding buffer to the\nnetwork stack (NULLing the pointer), and increments `cur_rx` modulo the\nring size. After the loop exits, stmmac_rx_refill(), which bookmarks its\nposition with `dirty_rx`, allocates fresh buffers and rearms the\ndescriptors (setting OWN=1). If it fails any allocation, it simply stops\nearly (leaving OWN=0) and will retry where it left off when next called.\n\nThis means descriptors have a three-stage lifecycle (terms my own):\n- `empty` (OWN=1, buffer valid)\n- `full` (OWN=0, buffer valid and populated)\n- `dirty` (OWN=0, buffer NULL)\n\nBut because stmmac_rx() only checks OWN, it confuses `full`/`dirty`. In\nthe past (see 'Fixes:'), there was a bug where the loop could cycle\n`cur_rx` all the way back to the first descriptor it dirtied, resulting\nin a NULL dereference when mistaken for `full`. The aforementioned\ncommit resolved that *specific* failure by capping the loop's iteration\nlimit at `dma_rx_size - 1`, but this is only a partial fix: if the\nprevious stmmac_rx_refill() didn't complete, then there are leftover\n`dirty` descriptors that the loop might encounter without needing to\ncycle fully around. The current code therefore panics (see 'Closes:')\nwhen stmmac_rx_refill() is memory-starved long enough for `cur_rx` to\ncatch up to `dirty_rx`.\n\nFix this by explicitly checking, before advancing `cur_rx`, if the next\nentry is dirty; exit the loop if so. This prevents processing of the\nfinal, used descriptor until stmmac_rx_refill() succeeds, but\nfully prevents the `cur_rx == dirty_rx` ambiguity as the previous bugfix\nintended: so remove the clamp as well. Since stmmac_rx_zc() is a\ncopy-paste-and-tweak of stmmac_rx() and the code structure is identical,\nany fix to stmmac_rx() will also need a corresponding fix for\nstmmac_rx_zc(). Therefore, apply the same check there.\n\nIn stmmac_rx() (not stmmac_rx_zc()), a related bug remains: after the\nMAC sets OWN=0 on the final descriptor, it will be unable to send any\nfurther DMA-complete IRQs until it's given more `empty` descriptors.\nCurrently, the driver simply *hopes* that the next stmmac_rx_refill()\nsucceeds, risking an indefinite stall of the receive process if not. But\nthis is not a regression, so it can be addressed in a future change."}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","baseScore":7.5,"baseSeverity":"HIGH"}}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/net/ethernet/stmicro/stmmac/stmmac_main.c"],"versions":[{"version":"7414a28de1b3b028714859078c00a874f9feff52","lessThan":"fdeb95b1fc7de25c9362990efb9996a8d761055c","status":"affected","versionType":"git"},{"version":"779334e59850f863bf34665e0ff0b6faf126873b","lessThan":"e1c50b273298c7cd9b08b113e7a7598b531a02f5","status":"affected","versionType":"git"},{"version":"b6cb4541853c7ee512111b0e7ddf3cb66c99c137","lessThan":"5c910f7708e3c507b037ca91ca5b09f8cfe71e65","status":"affected","versionType":"git"},{"version":"b6cb4541853c7ee512111b0e7ddf3cb66c99c137","lessThan":"4af2e62cbcda575a174acd230c3f3a208135e16d","status":"affected","versionType":"git"},{"version":"b6cb4541853c7ee512111b0e7ddf3cb66c99c137","lessThan":"950cb436165aad0f8f2cd49da3cd07677465bcde","status":"affected","versionType":"git"},{"version":"b6cb4541853c7ee512111b0e7ddf3cb66c99c137","lessThan":"0bb05e6adfa99a2ea1fee1125cc0953409f83ed8","status":"affected","versionType":"git"},{"version":"b435b4573240b5530830a1a60e005c6fcfd928a0","status":"affected","versionType":"git"},{"version":"6.1.64","lessThan":"6.1.176","status":"affected","versionType":"semver"},{"version":"6.6.3","lessThan":"6.6.140","status":"affected","versionType":"semver"},{"version":"6.5.13","lessThan":"6.6","status":"affected","versionType":"semver"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/net/ethernet/stmicro/stmmac/stmmac_main.c"],"versions":[{"version":"6.7","status":"affected"},{"version":"0","lessThan":"6.7","status":"unaffected","versionType":"semver"},{"version":"6.1.176","lessThanOrEqual":"6.1.*","status":"unaffected","versionType":"semver"},{"version":"6.6.140","lessThanOrEqual":"6.6.*","status":"unaffected","versionType":"semver"},{"version":"6.12.88","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.18.30","lessThanOrEqual":"6.18.*","status":"unaffected","versionType":"semver"},{"version":"7.0.7","lessThanOrEqual":"7.0.*","status":"unaffected","versionType":"semver"},{"version":"7.1","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":"6.1.64","versionEndExcluding":"6.1.176"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.6.3","versionEndExcluding":"6.6.140"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.7","versionEndExcluding":"6.12.88"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.7","versionEndExcluding":"6.18.30"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.7","versionEndExcluding":"7.0.7"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.7","versionEndExcluding":"7.1"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.5.13"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/fdeb95b1fc7de25c9362990efb9996a8d761055c"},{"url":"https://git.kernel.org/stable/c/e1c50b273298c7cd9b08b113e7a7598b531a02f5"},{"url":"https://git.kernel.org/stable/c/5c910f7708e3c507b037ca91ca5b09f8cfe71e65"},{"url":"https://git.kernel.org/stable/c/4af2e62cbcda575a174acd230c3f3a208135e16d"},{"url":"https://git.kernel.org/stable/c/950cb436165aad0f8f2cd49da3cd07677465bcde"},{"url":"https://git.kernel.org/stable/c/0bb05e6adfa99a2ea1fee1125cc0953409f83ed8"}],"title":"net: stmmac: Prevent NULL deref when RX memory exhausted","x_generator":{"engine":"bippy-1.2.0"}}}}