{"cve":"CVE-2026-23255","nvd":{"published":"2026-03-18T18:16:23.687","modified":"2026-10-15T02:18:44.980","status":"Modified","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: add proper RCU protection to /proc/net/ptype\n\nYin Fengwei reported an RCU stall in ptype_seq_show() and provided\na patch.\n\nReal issue is that ptype_seq_next() and ptype_seq_show() violate\nRCU rules.\n\nptype_seq_show() runs under rcu_read_lock(), and reads pt->dev\nto get device name without any barrier.\n\nAt the same time, concurrent writers can remove a packet_type structure\n(which is correctly freed after an RCU grace period) and clear pt->dev\nwithout an RCU grace period.\n\nDefine ptype_iter_state to carry a dev pointer along seq_net_private:\n\nstruct ptype_iter_state {\n\tstruct seq_net_private\tp;\n\tstruct net_device\t*dev; // added in this patch\n};\n\nWe need to record the device pointer in ptype_get_idx() and\nptype_seq_next() so that ptype_seq_show() is safe against\nconcurrent pt->dev changes.\n\nWe also need to add full RCU protection in ptype_seq_next().\n(Missing READ_ONCE() when reading list.next values)\n\nMany thanks to Dong Chenchen for providing a repro.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","score":5.5},"cwes":[],"references":["https://git.kernel.org/stable/c/002a73470b56848e4c81efeaaedd471e92d66d8d","https://git.kernel.org/stable/c/589a530ae44d0c80f523fcfd1a15af8087f27d35","https://git.kernel.org/stable/c/dcefd3f0b9ed8288654c75254bdcee8e1085e861","https://git.kernel.org/stable/c/e974a10a52618f7f57a4bce173a0ed96acd4e5dc","https://git.kernel.org/stable/c/f613e8b4afea0cd17c7168e8b00e25bc8d33175d"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-19T22:26:19.218427112+00:00"},"epss":{"cve":"CVE-2026-23255","score":0.00119,"percentile":0.01736,"date":"2026-10-25"},"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."]}