{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-46306", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-05-13T15:03:33.111Z", "datePublished": "2026-06-08T15:46:33.936Z", "dateUpdated": "2026-08-05T12:31:08.733Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:31:08.733Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nflow_dissector: do not dissect PPPoE PFC frames\n\nRFC 2516 Section 7 states that Protocol Field Compression (PFC) is NOT\nRECOMMENDED for PPPoE. In practice, pppd does not support negotiating\nPFC for PPPoE sessions, and the flow dissector driver has assumed an\nuncompressed frame until the blamed commit.\n\nDuring the review process of that commit [1], support for PFC is\nsuggested. However, having a compressed (1-byte) protocol field means\nthe subsequent PPP payload is shifted by one byte, causing 4-byte\nmisalignment for the network header and an unaligned access exception\non some architectures.\n\nThe exception can be reproduced by sending a PPPoE PFC frame to an\nethernet interface of a MIPS board, with RPS enabled, even if no PPPoE\nsession is active on that interface:\n\n$ 0 : 00000000 80c40000 00000000 85144817\n$ 4 : 00000008 00000100 80a75758 81dc9bb8\n$ 8 : 00000010 8087ae2c 0000003d 00000000\n$12 : 000000e0 00000039 00000000 00000000\n$16 : 85043240 80a75758 81dc9bb8 00006488\n$20 : 0000002f 00000007 85144810 80a70000\n$24 : 81d1bda0 00000000\n$28 : 81dc8000 81dc9aa8 00000000 805ead08\nHi : 00009d51\nLo : 2163358a\nepc : 805e91f0 __skb_flow_dissect+0x1b0/0x1b50\nra : 805ead08 __skb_get_hash_net+0x74/0x12c\nStatus: 11000403 KERNEL EXL IE\nCause : 40800010 (ExcCode 04)\nBadVA : 85144817\nPrId : 0001992f (MIPS 1004Kc)\nCall Trace:\n[<805e91f0>] __skb_flow_dissect+0x1b0/0x1b50\n[<805ead08>] __skb_get_hash_net+0x74/0x12c\n[<805ef330>] get_rps_cpu+0x1b8/0x3fc\n[<805fca70>] netif_receive_skb_list_internal+0x324/0x364\n[<805fd120>] napi_complete_done+0x68/0x2a4\n[<8058de5c>] mtk_napi_rx+0x228/0xfec\n[<805fd398>] __napi_poll+0x3c/0x1c4\n[<805fd754>] napi_threaded_poll_loop+0x234/0x29c\n[<805fd848>] napi_threaded_poll+0x8c/0xb0\n[<80053544>] kthread+0x104/0x12c\n[<80002bd8>] ret_from_kernel_thread+0x14/0x1c\n\nCode: 02d51821 1060045b 00000000 <8c640000> 3084000f 2c820005 144001a2 00042080 8e220000\n\nTo reduce the attack surface and maintain performance, do not process\nPPPoE PFC frames.\n\n[1] https://lore.kernel.org/r/20220630231016.GA392@debian.home" } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "baseScore": 7.5, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:N - The flaw is triggered by a crafted PPPoE session Ethernet frame received on a network interface and processed in the core packet-receive path (NAPI → `netif_receive_skb_list_internal` → `get_rps_cpu` → `__skb_get_hash_net` → `__skb_flow_dissect`), which matches kernel guidance for net-stack bugs reachable via received packets.\nAC:L - An attacker fully controls the malicious PPPoE PFC frame contents; once RPS (or another flow-hash caller such as tc flower ingress) is active on the target interface, sending the frame reliably reproduces the misaligned IPv4 header access and kernel exception without races or victim-specific timing.\nPR:N - Exploitation requires only the ability to transmit Ethernet frames to the victim interface; no local account, capabilities, or PPPoE session establishment is needed, as confirmed by the fix commit reproducing the crash with no active PPPoE session.\nUI:N - No victim user action is required beyond normal network operation; the kernel processes the injected frame automatically during receive-side RPS flow hashing.\nS:U - Impact is confined to kernel crash/DoS on the affected host; there is no cross-boundary escape from a sandbox, VM guest, or separate security authority.\nC:N - The bug causes an unaligned load fault while parsing attacker-supplied skb data at a wrong offset; it does not perform an out-of-bounds read of kernel memory or disclose kernel secrets, only misreads bytes within the crafted packet before faulting.\nI:N - There is no memory corruption, arbitrary write, or type confusion; the failure mode is a load-address exception on strict-alignment architectures (e.g., MIPS) without modifying kernel or application data.\nA:H - The documented impact is a kernel exception/oops in `__skb_flow_dissect` (MIPS ExcCode 04 unaligned access), which crashes or panics the system and can be retriggered remotely by resending the malicious frame." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/core/flow_dissector.c" ], "versions": [ { "version": "10f665b52a75df6eb26ddebbbc072ee264183731", "lessThan": "e7c811ca372d53c2be7d01a1614e71fae1054836", "status": "affected", "versionType": "git" }, { "version": "d7e541e86122d21f71eb71c5dfa7fb1eb6623fe8", "lessThan": "abc5bc84e0f2edc7ea2d437afa6ef3fe1fc43200", "status": "affected", "versionType": "git" }, { "version": "46126db9c86110e5fc1e369b9bb89735ddefdae4", "lessThan": "18ae9eacfc95cc715c0606b2c86e8aa8a86cf3e3", "status": "affected", "versionType": "git" }, { "version": "46126db9c86110e5fc1e369b9bb89735ddefdae4", "lessThan": "db104b0d8a7856397c0469d83a4289adf7c54863", "status": "affected", "versionType": "git" }, { "version": "46126db9c86110e5fc1e369b9bb89735ddefdae4", "lessThan": "6044392d9cace3a3672b02c8bc7d38b502e51734", "status": "affected", "versionType": "git" }, { "version": "46126db9c86110e5fc1e369b9bb89735ddefdae4", "lessThan": "0d00b9015069712944934bab09eaa6c542143049", "status": "affected", "versionType": "git" }, { "version": "46126db9c86110e5fc1e369b9bb89735ddefdae4", "lessThan": "7c93f353eab4ea911e394630f07d72e040a729d8", "status": "affected", "versionType": "git" }, { "version": "46126db9c86110e5fc1e369b9bb89735ddefdae4", "lessThan": "d6c19b31a3c1d519fabdcf0aa239e6b6109b9473", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/core/flow_dissector.c" ], "versions": [ { "version": "6.0", "status": "affected" }, { "version": "0", "lessThan": "6.0", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.175", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.140", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.88", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.30", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.0.7", "lessThanOrEqual": "7.0.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.1", "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": "6.0", "versionEndExcluding": "6.1.175" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.0", "versionEndExcluding": "6.6.140" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.0", "versionEndExcluding": "6.12.88" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.0", "versionEndExcluding": "6.18.30" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.0", "versionEndExcluding": "7.0.7" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.0", "versionEndExcluding": "7.1" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/e7c811ca372d53c2be7d01a1614e71fae1054836" }, { "url": "https://git.kernel.org/stable/c/abc5bc84e0f2edc7ea2d437afa6ef3fe1fc43200" }, { "url": "https://git.kernel.org/stable/c/18ae9eacfc95cc715c0606b2c86e8aa8a86cf3e3" }, { "url": "https://git.kernel.org/stable/c/db104b0d8a7856397c0469d83a4289adf7c54863" }, { "url": "https://git.kernel.org/stable/c/6044392d9cace3a3672b02c8bc7d38b502e51734" }, { "url": "https://git.kernel.org/stable/c/0d00b9015069712944934bab09eaa6c542143049" }, { "url": "https://git.kernel.org/stable/c/7c93f353eab4ea911e394630f07d72e040a729d8" }, { "url": "https://git.kernel.org/stable/c/d6c19b31a3c1d519fabdcf0aa239e6b6109b9473" } ], "title": "flow_dissector: do not dissect PPPoE PFC frames", "x_generator": { "engine": "bippy-1.2.0" } } } }