{"cve":"CVE-2021-47261","nvd":{"published":"2024-05-21T15:15:14.770","modified":"2026-08-04T10:16:55.687","status":"Modified","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nIB/mlx5: Fix initializing CQ fragments buffer\n\nThe function init_cq_frag_buf() can be called to initialize the current CQ\nfragments buffer cq->buf, or the temporary cq->resize_buf that is filled\nduring CQ resize operation.\n\nHowever, the offending commit started to use function get_cqe() for\ngetting the CQEs, the issue with this change is that get_cqe() always\nreturns CQEs from cq->buf, which leads us to initialize the wrong buffer,\nand in case of enlarging the CQ we try to access elements beyond the size\nof the current cq->buf and eventually hit a kernel panic.\n\n [exception RIP: init_cq_frag_buf+103]\n  [ffff9f799ddcbcd8] mlx5_ib_resize_cq at ffffffffc0835d60 [mlx5_ib]\n  [ffff9f799ddcbdb0] ib_resize_cq at ffffffffc05270df [ib_core]\n  [ffff9f799ddcbdc0] llt_rdma_setup_qp at ffffffffc0a6a712 [llt]\n  [ffff9f799ddcbe10] llt_rdma_cc_event_action at ffffffffc0a6b411 [llt]\n  [ffff9f799ddcbe98] llt_rdma_client_conn_thread at ffffffffc0a6bb75 [llt]\n  [ffff9f799ddcbec8] kthread at ffffffffa66c5da1\n  [ffff9f799ddcbf50] ret_from_fork_nospec_begin at ffffffffa6d95ddd\n\nFix it by getting the needed CQE by calling mlx5_frag_buf_get_wqe() that\ntakes the correct source buffer as a parameter.","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-706"],"references":["https://git.kernel.org/stable/c/1ec2dcd680c71d0d36fa25638b327a468babd5c9","https://git.kernel.org/stable/c/2ba0aa2feebda680ecfc3c552e867cf4d1b05a3a","https://git.kernel.org/stable/c/3e670c54eda238cb8a1ea93538a79ae89285c1c4","https://git.kernel.org/stable/c/91f7fdc4cc10542ca1045c06aad23365f0d067e0","https://git.kernel.org/stable/c/e3ecd9c09fcc10cf6b2bc67e2990c397c40a8c26"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-19T21:50:30.954589733+00:00"},"epss":{"cve":"CVE-2021-47261","score":0.00236,"percentile":0.14644,"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."]}