{"cve":"CVE-2026-53300","nvd":{"published":"2026-06-26T20:17:23.200","modified":"2026-07-08T03:38:42.627","status":"Analyzed","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: enetc: fix NTMP DMA use-after-free issue\n\nThe AI-generated review reported a potential DMA use-after-free issue\n[1]. If netc_xmit_ntmp_cmd() times out and returns an error, the pending\ncommand is not explicitly aborted, while ntmp_free_data_mem()\nunconditionally frees the DMA buffer. If the buffer has already been\nreallocated elsewhere, this may lead to silent memory corruption. Because\nthe hardware eventually processes the pending command and perform a DMA\nwrite of the response to the physical address of the freed buffer.\n\nTo resolve this issue, this patch does the following modifications:\n\n1. Convert cbdr->ring_lock from a spinlock to a mutex\n\nThe lock was originally a spinlock in case NTMP operations might be\ninvoked from atomic context. After downstream support for all NTMP\ntables, no such usage has materialized. A mutex lock is now required\nbecause the driver now needs to reclaim used BDs and release associated\nDMA memory within the lock's context, while dma_free_coherent() might\nsleep.\n\n2. Introduce software command BD (struct netc_swcbd)\n\nThe hardware write-back overwrites the addr and len fields of the BD,\nso the driver cannot rely on the hardware BD to free the associated DMA\nmemory. The driver now maintains a software shadow BD storing the DMA\nbuffer pointer, DMA address, and size. And netc_xmit_ntmp_cmd() only\nreclaims older BDs when the number of used BDs reaches\nNETC_CBDR_CLEAN_WORK (16). The software BD enables correct DMA memory\nrelease. With this, struct ntmp_dma_buf and ntmp_free_data_mem() are no\nlonger needed and are removed.\n\n3. Require callers to hold ring_lock across netc_xmit_ntmp_cmd()\n\nnetc_xmit_ntmp_cmd() releases the ring_lock before the caller finishes\nconsuming the response. At this point, if a concurrent thread submits\na new command, it may trigger ntmp_clean_cbdr() and free the DMA buffer\nwhile it is still in use. Move ring_lock ownership to the caller to\nensure the response buffer cannot be reclaimed prematurely. So the\nhelpers ntmp_select_and_lock_cbdr() and ntmp_unlock_cbdr() are added.\n\nThese changes eliminate the DMA use-after-free condition and ensure safe\nand consistent BD reclamation and DMA buffer lifecycle management.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","score":7.8},"cwes":["CWE-416"],"references":["https://git.kernel.org/stable/c/37c8933064be714ee672b0a0523c2fd045b73b3d","https://git.kernel.org/stable/c/3cade698881eb238f88cbbfec82acc2110440a3f","https://git.kernel.org/stable/c/655d9ce9b1d3db0aa5271acb5e5101c66bd0d58b"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-19T22:41:17.107060303+00:00"},"epss":{"cve":"CVE-2026-53300","score":0.00168,"percentile":0.06156,"date":"2026-10-31"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}