{"id":"CVE-2026-53300","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-53300","generatedAt":"2026-10-28T02:18:29.452Z","title":"In the Linux kernel, the following vulnerability has been resolved: net: enetc: fix NTMP DMA use-after-free issue The AI-generated review reported a potential DMA use-after-free issue [1].","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.","published":"2026-06-26T20:17:23.000Z","lastModified":"2026-07-08T03:38:43.000Z","status":"Analyzed","sourceIdentifier":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","cvss":{"version":"3.1","score":7.8,"severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"},"cwe":["CWE-416"],"affected":["linux/linux kernel"],"epss":{"score":0.00168,"percentile":0.06141,"date":"2026-10-26","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"high","text":"High impact if exploited, but EPSS currently rates exploitation as unlikely (0.17%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit."},"changes":[],"references":[{"url":"https://git.kernel.org/stable/c/37c8933064be714ee672b0a0523c2fd045b73b3d","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/3cade698881eb238f88cbbfec82acc2110440a3f","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/655d9ce9b1d3db0aa5271acb5e5101c66bd0d58b","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-53300","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}