{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2021-47013", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2024-02-27T18:42:55.953Z", "datePublished": "2024-02-28T08:13:30.905Z", "dateUpdated": "2026-08-05T08:45:34.504Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T08:45:34.504Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet:emac/emac-mac: Fix a use after free in emac_mac_tx_buf_send\n\nIn emac_mac_tx_buf_send, it calls emac_tx_fill_tpd(..,skb,..).\nIf some error happens in emac_tx_fill_tpd(), the skb will be freed via\ndev_kfree_skb(skb) in error branch of emac_tx_fill_tpd().\nBut the freed skb is still used via skb->len by netdev_sent_queue(,skb->len).\n\nAs i observed that emac_tx_fill_tpd() haven't modified the value of skb->len,\nthus my patch assigns skb->len to 'len' before the possible free and\nuse 'len' instead of skb->len later." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "baseScore": 9.8, "baseSeverity": "CRITICAL" }, "scenarios": [ { "lang": "en", "value": "AV:N - The bug is in the Qualcomm EMAC ndo_start_xmit path (emac_start_xmit → emac_mac_tx_buf_send), used on network-facing FSM9900/QDF platforms; a remote peer can drive TX via ARP/ICMP/TCP replies or forwarded traffic through this NIC, matching other ethernet TX CVEs.\nAC:L - An attacker can flood traffic to raise DMA/swiotlb pressure until dma_mapping_error() hits; once that failure occurs the UAF of skb->len is deterministic, as scored for similar dma_mapping_error TX bugs (e.g. CVE-2024-50170).\nPR:N - No authentication or capability check sits on this path—unauthenticated remote traffic that elicits kernel TX, or an unprivileged local socket send, reaches emac_mac_tx_buf_send.\nUI:N - No victim action is required; ordinary network traffic or local sends autonomously exercise the transmit path.\nS:U - The UAF corrupts/abuses kernel skb and BQL state within the same host security authority; the TX ring produce index is rolled back on the error path so no IOMMU/DMA boundary is crossed.\nC:H - This is a use-after-free of an sk_buff: after dev_kfree_skb() the freed object can be reclaimed via heap spray, and UAF of skb metadata is treated as enabling arbitrary kernel memory disclosure primitives.\nI:H - Use-after-free of the skb enables heap reuse/type confusion and attacker-controlled BQL byte accounting via the post-free skb->len read, which is leverageable for memory corruption and control-flow impact.\nA:H - Dereferencing the freed skb can oops if the object is poisoned or unmapped, and the post-free netdev_sent_queue() permanently inflates BQL without a matching completion, enabling TX queue stall or kernel crash." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/net/ethernet/qualcomm/emac/emac-mac.c" ], "versions": [ { "version": "b9b17debc69d27cd55e21ee51a5ba7fc50a426cf", "lessThan": "c7f75d11fe72913d2619f97b2334b083cd7bb955", "status": "affected", "versionType": "git" }, { "version": "b9b17debc69d27cd55e21ee51a5ba7fc50a426cf", "lessThan": "dc1b438a35773d030be0ee80d9c635c3e558a322", "status": "affected", "versionType": "git" }, { "version": "b9b17debc69d27cd55e21ee51a5ba7fc50a426cf", "lessThan": "16d8c44be52e3650917736d45f5904384a9da834", "status": "affected", "versionType": "git" }, { "version": "b9b17debc69d27cd55e21ee51a5ba7fc50a426cf", "lessThan": "55fcdd1258faaecca74b91b88cc0921f9edd775d", "status": "affected", "versionType": "git" }, { "version": "b9b17debc69d27cd55e21ee51a5ba7fc50a426cf", "lessThan": "9dc373f74097edd0e35f3393d6248eda8d1ba99d", "status": "affected", "versionType": "git" }, { "version": "b9b17debc69d27cd55e21ee51a5ba7fc50a426cf", "lessThan": "8c06f34785068b87e2b560534c77c163d6c6dca7", "status": "affected", "versionType": "git" }, { "version": "b9b17debc69d27cd55e21ee51a5ba7fc50a426cf", "lessThan": "e407495ba6788a67d1bd41714158c079e340879b", "status": "affected", "versionType": "git" }, { "version": "b9b17debc69d27cd55e21ee51a5ba7fc50a426cf", "lessThan": "6d72e7c767acbbdd44ebc7d89c6690b405b32b57", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/net/ethernet/qualcomm/emac/emac-mac.c" ], "versions": [ { "version": "4.9", "status": "affected" }, { "version": "0", "lessThan": "4.9", "status": "unaffected", "versionType": "semver" }, { "version": "4.9.269", "lessThanOrEqual": "4.9.*", "status": "unaffected", "versionType": "semver" }, { "version": "4.14.233", "lessThanOrEqual": "4.14.*", "status": "unaffected", "versionType": "semver" }, { "version": "4.19.191", "lessThanOrEqual": "4.19.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.4.119", "lessThanOrEqual": "5.4.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.37", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.11.21", "lessThanOrEqual": "5.11.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.12.4", "lessThanOrEqual": "5.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.13", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.9", "versionEndExcluding": "4.9.269" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.9", "versionEndExcluding": "4.14.233" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.9", "versionEndExcluding": "4.19.191" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.9", "versionEndExcluding": "5.4.119" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.9", "versionEndExcluding": "5.10.37" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.9", "versionEndExcluding": "5.11.21" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.9", "versionEndExcluding": "5.12.4" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.9", "versionEndExcluding": "5.13" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/c7f75d11fe72913d2619f97b2334b083cd7bb955" }, { "url": "https://git.kernel.org/stable/c/dc1b438a35773d030be0ee80d9c635c3e558a322" }, { "url": "https://git.kernel.org/stable/c/16d8c44be52e3650917736d45f5904384a9da834" }, { "url": "https://git.kernel.org/stable/c/55fcdd1258faaecca74b91b88cc0921f9edd775d" }, { "url": "https://git.kernel.org/stable/c/9dc373f74097edd0e35f3393d6248eda8d1ba99d" }, { "url": "https://git.kernel.org/stable/c/8c06f34785068b87e2b560534c77c163d6c6dca7" }, { "url": "https://git.kernel.org/stable/c/e407495ba6788a67d1bd41714158c079e340879b" }, { "url": "https://git.kernel.org/stable/c/6d72e7c767acbbdd44ebc7d89c6690b405b32b57" } ], "title": "net:emac/emac-mac: Fix a use after free in emac_mac_tx_buf_send", "x_generator": { "engine": "bippy-1.2.0" } }, "adp": [ { "title": "CISA ADP Vulnrichment", "metrics": [ { "other": { "type": "ssvc", "content": { "id": "CVE-2021-47013", "role": "CISA Coordinator", "options": [ { "Exploitation": "none" }, { "Automatable": "no" }, { "Technical Impact": "partial" } ], "version": "2.0.3", "timestamp": "2024-02-28T19:56:27.719807Z" } } } ], "providerMetadata": { "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2024-06-04T17:13:43.156Z" } }, { "providerMetadata": { "orgId": "af854a3a-2127-422b-91ae-364da2661108", "shortName": "CVE", "dateUpdated": "2024-08-04T05:24:39.713Z" }, "title": "CVE Program Container", "references": [ { "url": "https://git.kernel.org/stable/c/c7f75d11fe72913d2619f97b2334b083cd7bb955", "tags": [ "x_transferred" ] }, { "url": "https://git.kernel.org/stable/c/dc1b438a35773d030be0ee80d9c635c3e558a322", "tags": [ "x_transferred" ] }, { "url": "https://git.kernel.org/stable/c/16d8c44be52e3650917736d45f5904384a9da834", "tags": [ "x_transferred" ] }, { "url": "https://git.kernel.org/stable/c/55fcdd1258faaecca74b91b88cc0921f9edd775d", "tags": [ "x_transferred" ] }, { "url": "https://git.kernel.org/stable/c/9dc373f74097edd0e35f3393d6248eda8d1ba99d", "tags": [ "x_transferred" ] }, { "url": "https://git.kernel.org/stable/c/8c06f34785068b87e2b560534c77c163d6c6dca7", "tags": [ "x_transferred" ] }, { "url": "https://git.kernel.org/stable/c/e407495ba6788a67d1bd41714158c079e340879b", "tags": [ "x_transferred" ] }, { "url": "https://git.kernel.org/stable/c/6d72e7c767acbbdd44ebc7d89c6690b405b32b57", "tags": [ "x_transferred" ] } ] } ] } }