{"id":"CVE-2025-21954","summary":"netmem: prevent TX of unreadable skbs","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nnetmem: prevent TX of unreadable skbs\n\nCurrently on stable trees we have support for netmem/devmem RX but not\nTX. It is not safe to forward/redirect an RX unreadable netmem packet\ninto the device's TX path, as the device may call dma-mapping APIs on\ndma addrs that should not be passed to it.\n\nFix this by preventing the xmit of unreadable skbs.\n\nTested by configuring tc redirect:\n\nsudo tc qdisc add dev eth1 ingress\nsudo tc filter add dev eth1 ingress protocol ip prio 1 flower ip_proto \\\n\ttcp src_ip 192.168.1.12 action mirred egress redirect dev eth1\n\nBefore, I see unreadable skbs in the driver's TX path passed to dma\nmapping APIs.\n\nAfter, I don't see unreadable skbs in the driver's TX path passed to dma\nmapping APIs.","modified":"2026-04-02T12:45:17.697983Z","published":"2025-04-01T15:46:55.226Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/21xxx/CVE-2025-21954.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/1c17c8ced25c5fbe424c7ad7ea11d33014a986b1"},{"type":"WEB","url":"https://git.kernel.org/stable/c/454825019d2f0c59e5174ece9e713f45ad80beff"},{"type":"WEB","url":"https://git.kernel.org/stable/c/f3600c867c99a2cc8038680ecf211089c50e7971"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/21xxx/CVE-2025-21954.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2025-21954"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"65249feb6b3df9e17bab5911ee56fa7b0971e231"},{"fixed":"454825019d2f0c59e5174ece9e713f45ad80beff"},{"fixed":"1c17c8ced25c5fbe424c7ad7ea11d33014a986b1"},{"fixed":"f3600c867c99a2cc8038680ecf211089c50e7971"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-21954.json"}}],"schema_version":"1.7.5"}