{"cve":"CVE-2025-39917","nvd":{"published":"2025-10-01T08:15:34.887","modified":"2026-10-19T21:10:00.160","status":"Modified","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Fix out-of-bounds dynptr write in bpf_crypto_crypt\n\nStanislav reported that in bpf_crypto_crypt() the destination dynptr's\nsize is not validated to be at least as large as the source dynptr's\nsize before calling into the crypto backend with 'len = src_len'. This\ncan result in an OOB write when the destination is smaller than the\nsource.\n\nConcretely, in mentioned function, psrc and pdst are both linear\nbuffers fetched from each dynptr:\n\n  psrc = __bpf_dynptr_data(src, src_len);\n  [...]\n  pdst = __bpf_dynptr_data_rw(dst, dst_len);\n  [...]\n  err = decrypt ?\n        ctx->type->decrypt(ctx->tfm, psrc, pdst, src_len, piv) :\n        ctx->type->encrypt(ctx->tfm, psrc, pdst, src_len, piv);\n\nThe crypto backend expects pdst to be large enough with a src_len length\nthat can be written. Add an additional src_len > dst_len check and bail\nout if it's the case. Note that these kfuncs are accessible under root\nprivileges only.","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-787"],"references":["https://git.kernel.org/stable/c/0126358df12d6f476f79251d9c398ac5c1b3062d","https://git.kernel.org/stable/c/c4be24ef0510c146dca4671effb127e97631534b","https://git.kernel.org/stable/c/f9bb6ffa7f5ad0f8ee0f53fc4a10655872ee4a14"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-21T03:43:09.190223697+00:00"},"epss":{"cve":"CVE-2025-39917","score":0.00154,"percentile":0.04509,"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."]}