{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2025-38574", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2025-04-16T04:51:24.025Z", "datePublished": "2025-08-19T17:02:53.866Z", "dateUpdated": "2026-08-05T12:03:02.855Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:03:02.855Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\npptp: ensure minimal skb length in pptp_xmit()\n\nCommit aabc6596ffb3 (\"net: ppp: Add bound checking for skb data\non ppp_sync_txmung\") fixed ppp_sync_txmunge()\n\nWe need a similar fix in pptp_xmit(), otherwise we might\nread uninit data as reported by syzbot.\n\nBUG: KMSAN: uninit-value in pptp_xmit+0xc34/0x2720 drivers/net/ppp/pptp.c:193\n pptp_xmit+0xc34/0x2720 drivers/net/ppp/pptp.c:193\n ppp_channel_bridge_input drivers/net/ppp/ppp_generic.c:2290 [inline]\n ppp_input+0x1d6/0xe60 drivers/net/ppp/ppp_generic.c:2314\n pppoe_rcv_core+0x1e8/0x760 drivers/net/ppp/pppoe.c:379\n sk_backlog_rcv+0x142/0x420 include/net/sock.h:1148\n __release_sock+0x1d3/0x330 net/core/sock.c:3213\n release_sock+0x6b/0x270 net/core/sock.c:3767\n pppoe_sendmsg+0x15d/0xcb0 drivers/net/ppp/pppoe.c:904\n sock_sendmsg_nosec net/socket.c:712 [inline]\n __sock_sendmsg+0x330/0x3d0 net/socket.c:727\n ____sys_sendmsg+0x893/0xd80 net/socket.c:2566\n ___sys_sendmsg+0x271/0x3b0 net/socket.c:2620\n __sys_sendmmsg+0x2d9/0x7c0 net/socket.c:2709" } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H", "baseScore": 8.6, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:N - The defect is reached from received packets — `ppp_channel_bridge_input()` passes an unvalidated skb directly to `pptp_xmit()`, and the peer channel can be an internet-routable pppol2tp (UDP/1701) or PPTP-GRE session, whose data-plane frames carry attacker-chosen lengths; the syzbot trace itself shows the receive handler `pppoe_rcv_core()` driving this path.\nAC:L - The attacker simply sends a PPP payload shorter than 3 bytes (or one whose linear head is short); there is no race, no memory-layout dependency, and unlimited retries are possible since each malformed frame is processed independently.\nPR:N - L2TP/PPPoE/PPTP data-plane frames carry no per-packet authentication — only cleartext tunnel/session/call IDs — so an off-path or on-segment attacker who observes or guesses those IDs reaches `ppp_input()` with no credentials at all.\nUI:N - The bridged channel is part of the running relay configuration; the attacker triggers the read purely by transmitting a frame, with no action from any local user or administrator.\nS:U - The uninitialized read, the bogus `skb_pull()` and the resulting panic all occur inside the kernel's own networking authority; no hypervisor, IOMMU, or sandbox boundary is crossed.\nC:L - Up to three bytes of uninitialized kernel heap — stale tailroom left by a freed object, or the leading `flags`/`meta_len`/`nr_frags` fields of `skb_shared_info` past the linear data — are read; their values steer whether `ff 03` is prepended and whether a byte is stripped, giving the tunnel peer an observable oracle on kernel memory, but the read is bounded to fixed offsets and is not copied out wholesale.\nI:L - The uninitialized bytes decide `islcp` and the `skb_pull(skb, 1)` in the SC_COMP_PROT branch, so the kernel silently emits PPP frames with a stripped leading byte or spurious address/control framing, corrupting the tunneled data delivered to the peer; there is no arbitrary write or memory corruption.\nA:H - When the bridged skb is nonlinear with `skb_headlen() == 0` and the stale `data[0]` reads as zero under normally-negotiated PFC, `skb_pull(skb, 1)` drives `skb->len` below `skb->data_len` and `__skb_pull()` calls `BUG()`, panicking the machine; on KMSAN/`panic_on_warn` builds the uninit read alone is fatal." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/net/ppp/pptp.c" ], "versions": [ { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "97b8c5d322c5c0038cac4bc56fdbe237d0be426f", "status": "affected", "versionType": "git" }, { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "26672f1679b143aa34fca0b6046b7fd0c184770d", "status": "affected", "versionType": "git" }, { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "5de7513f38f3c19c0610294ee478242bea356f8c", "status": "affected", "versionType": "git" }, { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "504cc4ab91073d2ac7404ad146139f86ecee7193", "status": "affected", "versionType": "git" }, { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "5005d24377378a20e5c0e53052fc4ebdcdcbc611", "status": "affected", "versionType": "git" }, { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "ea99b88b1999ebcb24d5d3a6b7910030f40d3bba", "status": "affected", "versionType": "git" }, { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "b7dcda76fd0615c0599c89f36873a6cd48e02dbb", "status": "affected", "versionType": "git" }, { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "1a04db0fd75cb6034fc27a56b67b3b8b9022a98c", "status": "affected", "versionType": "git" }, { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "de9c4861fb42f0cd72da844c3c34f692d5895b7b", "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/ppp/pptp.c" ], "versions": [ { "version": "2.6.12", "status": "affected" }, { "version": "0", "lessThan": "2.6.12", "status": "unaffected", "versionType": "semver" }, { "version": "5.4.297", "lessThanOrEqual": "5.4.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.241", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.190", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.148", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.102", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.42", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.15.10", "lessThanOrEqual": "6.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.16.1", "lessThanOrEqual": "6.16.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.17", "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": "2.6.12", "versionEndExcluding": "5.4.297" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.12", "versionEndExcluding": "5.10.241" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.12", "versionEndExcluding": "5.15.190" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.12", "versionEndExcluding": "6.1.148" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.12", "versionEndExcluding": "6.6.102" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.12", "versionEndExcluding": "6.12.42" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.12", "versionEndExcluding": "6.15.10" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.12", "versionEndExcluding": "6.16.1" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.12", "versionEndExcluding": "6.17" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/97b8c5d322c5c0038cac4bc56fdbe237d0be426f" }, { "url": "https://git.kernel.org/stable/c/26672f1679b143aa34fca0b6046b7fd0c184770d" }, { "url": "https://git.kernel.org/stable/c/5de7513f38f3c19c0610294ee478242bea356f8c" }, { "url": "https://git.kernel.org/stable/c/504cc4ab91073d2ac7404ad146139f86ecee7193" }, { "url": "https://git.kernel.org/stable/c/5005d24377378a20e5c0e53052fc4ebdcdcbc611" }, { "url": "https://git.kernel.org/stable/c/ea99b88b1999ebcb24d5d3a6b7910030f40d3bba" }, { "url": "https://git.kernel.org/stable/c/b7dcda76fd0615c0599c89f36873a6cd48e02dbb" }, { "url": "https://git.kernel.org/stable/c/1a04db0fd75cb6034fc27a56b67b3b8b9022a98c" }, { "url": "https://git.kernel.org/stable/c/de9c4861fb42f0cd72da844c3c34f692d5895b7b" } ], "title": "pptp: ensure minimal skb length in pptp_xmit()", "x_generator": { "engine": "bippy-1.2.0" } }, "adp": [ { "title": "CVE Program Container", "references": [ { "url": "https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html" }, { "url": "https://lists.debian.org/debian-lts-announce/2025/10/msg00007.html" } ], "providerMetadata": { "orgId": "af854a3a-2127-422b-91ae-364da2661108", "shortName": "CVE", "dateUpdated": "2025-11-03T17:40:01.333Z" } } ] } }