{"id":"CVE-2025-38502","url":"https://www.cyber-defence.io/tools/cve/CVE-2025-38502","generatedAt":"2026-10-28T10:47:19.458Z","title":"In the Linux kernel, the following vulnerability has been resolved: bpf: Fix oob access in cgroup local storage Lonial reported that an out-of-bounds access in cgroup local storage can be crafted via tail calls.","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Fix oob access in cgroup local storage\n\nLonial reported that an out-of-bounds access in cgroup local storage\ncan be crafted via tail calls. Given two programs each utilizing a\ncgroup local storage with a different value size, and one program\ndoing a tail call into the other. The verifier will validate each of\nthe indivial programs just fine. However, in the runtime context\nthe bpf_cg_run_ctx holds an bpf_prog_array_item which contains the\nBPF program as well as any cgroup local storage flavor the program\nuses. Helpers such as bpf_get_local_storage() pick this up from the\nruntime context:\n\n  ctx = container_of(current->bpf_ctx, struct bpf_cg_run_ctx, run_ctx);\n  storage = ctx->prog_item->cgroup_storage[stype];\n\n  if (stype == BPF_CGROUP_STORAGE_SHARED)\n    ptr = &READ_ONCE(storage->buf)->data[0];\n  else\n    ptr = this_cpu_ptr(storage->percpu_buf);\n\nFor the second program which was called from the originally attached\none, this means bpf_get_local_storage() will pick up the former\nprogram's map, not its own. With mismatching sizes, this can result\nin an unintended out-of-bounds access.\n\nTo fix this issue, we need to extend bpf_map_owner with an array of\nstorage_cookie[] to match on i) the exact maps from the original\nprogram if the second program was using bpf_get_local_storage(), or\nii) allow the tail call combination if the second program was not\nusing any of the cgroup local storage maps.","published":"2025-08-16T10:15:26.000Z","lastModified":"2026-10-15T22:18:43.000Z","status":"Modified","sourceIdentifier":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","cvss":{"version":"3.1","score":7.1,"severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H"},"cwe":["CWE-125"],"affected":["linux/linux kernel","debian/debian linux","siemens/simatic cn 4100 firmware"],"epss":{"score":0.00177,"percentile":0.07261,"date":"2026-10-27","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 (0.18%). 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/19341d5c59e8c7e8528e40f8663e99d67810473c","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/41688d1fc5d163a6c2c0e95c0419e2cb31a44648","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/66da7cee78590259b400e51a70622ccd41da7bb2","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/7acfa07c585e3d7a64654d38f0a5c762877d0b9b","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/abad3d0bad72a52137e0c350c59542d75ae4f513","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/c1c74584b9b4043c52e41fec415226e582d266a3","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html","tags":["Mailing List","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://cert-portal.siemens.com/productcert/html/ssa-032379.html","tags":["Third Party Advisory"],"source":"0b142b55-0307-4c5a-b3c9-f314f3fb7c5e"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2025-38502","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."}