{"id":"CVE-2023-53669","state":"PUBLISHED","title":"tcp: fix skb_copy_ubufs() vs BIG TCP","description":"In the Linux kernel, the following vulnerability has been resolved:\n\ntcp: fix skb_copy_ubufs() vs BIG TCP\n\nDavid Ahern reported crashes in skb_copy_ubufs() caused by TCP tx zerocopy\nusing hugepages, and skb length bigger than ~68 KB.\n\nskb_copy_ubufs() assumed it could copy all payload using up to\nMAX_SKB_FRAGS order-0 pages.\n\nThis assumption broke when BIG TCP was able to put up to 512 KB per skb.\n\nWe did not hit this bug at Google because we use CONFIG_MAX_SKB_FRAGS=45\nand limit gso_max_size to 180000.\n\nA solution is to use higher order pages if needed.\n\nv2: add missing __GFP_COMP, or we leak memory.","publishedAt":"2025-10-07T15:21:26.896Z","updatedAt":"2026-10-15T21:41:32.929Z","severity":{"score":7.8,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"7c4e983c4f3cf94fcd879730c6caa877e0768a4d","status":"affected","lessThan":"7fa93e39fbb0566019c388a8038a4d58552e0910","versionType":"git"},{"version":"7c4e983c4f3cf94fcd879730c6caa877e0768a4d","status":"affected","lessThan":"3c77a377877acbaf03cd7caa21d3644a5dd16301","versionType":"git"},{"version":"7c4e983c4f3cf94fcd879730c6caa877e0768a4d","status":"affected","lessThan":"9cd62f0ba465cf647c7d8c2ca7b0d99ea0c1328f","versionType":"git"},{"version":"7c4e983c4f3cf94fcd879730c6caa877e0768a4d","status":"affected","lessThan":"7e692df3933628d974acb9f5b334d2b3e885e2a6","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/core/skbuff.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.19","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.19","versionType":"semver"},{"version":"6.1.29","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.2.16","status":"unaffected","lessThanOrEqual":"6.2.*","versionType":"semver"},{"version":"6.3.3","status":"unaffected","lessThanOrEqual":"6.3.*","versionType":"semver"},{"version":"6.4","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/core/skbuff.c"]}],"references":["https://git.kernel.org/stable/c/7fa93e39fbb0566019c388a8038a4d58552e0910","https://git.kernel.org/stable/c/3c77a377877acbaf03cd7caa21d3644a5dd16301","https://git.kernel.org/stable/c/9cd62f0ba465cf647c7d8c2ca7b0d99ea0c1328f","https://git.kernel.org/stable/c/7e692df3933628d974acb9f5b334d2b3e885e2a6"],"weaknesses":[],"ingestedAt":"2026-10-29T20:06:33.064Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2023/53xxx/CVE-2023-53669.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2023-53669","state":"PUBLISHED","datePublished":"2025-10-07T15:21:26.896Z","dateUpdated":"2026-10-15T21:41:32.929Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2025-10-07T15:16:59.663Z"},"containers":{"cna":{"title":"tcp: fix skb_copy_ubufs() vs BIG TCP","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\ntcp: fix skb_copy_ubufs() vs BIG TCP\n\nDavid Ahern reported crashes in skb_copy_ubufs() caused by TCP tx zerocopy\nusing hugepages, and skb length bigger than ~68 KB.\n\nskb_copy_ubufs() assumed it could copy all payload using up to\nMAX_SKB_FRAGS order-0 pages.\n\nThis assumption broke when BIG TCP was able to put up to 512 KB per skb.\n\nWe did not hit this bug at Google because we use CONFIG_MAX_SKB_FRAGS=45\nand limit gso_max_size to 180000.\n\nA solution is to use higher order pages if needed.\n\nv2: add missing __GFP_COMP, or we leak memory."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"7c4e983c4f3cf94fcd879730c6caa877e0768a4d","status":"affected","lessThan":"7fa93e39fbb0566019c388a8038a4d58552e0910","versionType":"git"},{"version":"7c4e983c4f3cf94fcd879730c6caa877e0768a4d","status":"affected","lessThan":"3c77a377877acbaf03cd7caa21d3644a5dd16301","versionType":"git"},{"version":"7c4e983c4f3cf94fcd879730c6caa877e0768a4d","status":"affected","lessThan":"9cd62f0ba465cf647c7d8c2ca7b0d99ea0c1328f","versionType":"git"},{"version":"7c4e983c4f3cf94fcd879730c6caa877e0768a4d","status":"affected","lessThan":"7e692df3933628d974acb9f5b334d2b3e885e2a6","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/core/skbuff.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.19","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.19","versionType":"semver"},{"version":"6.1.29","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.2.16","status":"unaffected","lessThanOrEqual":"6.2.*","versionType":"semver"},{"version":"6.3.3","status":"unaffected","lessThanOrEqual":"6.3.*","versionType":"semver"},{"version":"6.4","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/core/skbuff.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/7fa93e39fbb0566019c388a8038a4d58552e0910"},{"url":"https://git.kernel.org/stable/c/3c77a377877acbaf03cd7caa21d3644a5dd16301"},{"url":"https://git.kernel.org/stable/c/9cd62f0ba465cf647c7d8c2ca7b0d99ea0c1328f"},{"url":"https://git.kernel.org/stable/c/7e692df3933628d974acb9f5b334d2b3e885e2a6"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":7.8,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:L - The vulnerable code only runs on locally-originated TX skbs carrying MSG_ZEROCOPY frags; received network packets never carry zcopy frags (skb_zcopy() is false, early return), so a remote peer cannot reach it. Triggering requires local socket/syscall activity.\nAC:L - The local attacker controls every precondition — enabling BIG TCP (CAP_NET_ADMIN via user namespace on a private netns device), using THP/hugepage-backed buffers, and sending MSG_ZEROCOPY payloads sized to overflow — so the overflow is reliably reproducible.\nPR:L - Exploitation requires running local code (MSG_ZEROCOPY sendmsg) and CAP_NET_ADMIN to raise gso_max_size, both available to a basic unprivileged user through an unprivileged user+network namespace. No real root is needed.\nUI:N - The attacker triggers the overflow entirely through its own socket operations; no action by another user is required.\nS:U - The out-of-bounds write corrupts kernel heap within the same kernel security authority; there is no crossing of a VM/IOMMU/sandbox boundary.\nC:H - The OOB write corrupts skb_shared_info frag page descriptors, which can be steered so kernel data is read/transmitted from attacker-influenced pages, and per guidance memory corruption leveragable for disclosure scores High.\nI:H - This is a controllable-size out-of-bounds heap write (frag descriptors written past the frags array), providing a write primitive suitable for control-flow hijacking or privilege escalation.\nA:H - The overflow reliably corrupts adjacent memory and was reported as causing kernel crashes (oops/panic), a full denial of service."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-05T09:15:25.435Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.19","versionEndExcluding":"6.1.29"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.19","versionEndExcluding":"6.2.16"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.19","versionEndExcluding":"6.3.3"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.19","versionEndExcluding":"6.4"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2023-53669","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"total"}],"version":"2.0.3","timestamp":"2026-10-15T21:36:19.702687Z"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-10-15T21:41:32.929Z"}}]}}}