{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2025-37749","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2025-04-16T04:51:23.937Z","datePublished":"2025-05-01T12:55:55.316Z","dateUpdated":"2026-08-05T11:57:13.771Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-08-05T11:57:13.771Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: ppp: Add bound checking for skb data on ppp_sync_txmung\n\nEnsure we have enough data in linear buffer from skb before accessing\ninitial bytes. This prevents potential out-of-bounds accesses\nwhen processing short packets.\n\nWhen ppp_sync_txmung receives an incoming package with an empty\npayload:\n(remote) gef➤  p *(struct pppoe_hdr *) (skb->head + skb->network_header)\n$18 = {\n\ttype = 0x1,\n\tver = 0x1,\n\tcode = 0x0,\n\tsid = 0x2,\n        length = 0x0,\n\ttag = 0xffff8880371cdb96\n}\n\nfrom the skb struct (trimmed)\n      tail = 0x16,\n      end = 0x140,\n      head = 0xffff88803346f400 \"4\",\n      data = 0xffff88803346f416 \":\\377\",\n      truesize = 0x380,\n      len = 0x0,\n      data_len = 0x0,\n      mac_len = 0xe,\n      hdr_len = 0x0,\n\nit is not safe to access data[2].\n\n[pabeni@redhat.com: fixed subj typo]"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H","baseScore":8.2,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:N - The vulnerable function is reached from `ppp_input()` via `ppp_channel_bridge_input()`, which forwards remotely received PPP frames directly to the sync-tty channel's `start_xmit` before any length validation; the feeding channels include pppol2tp (UDP/IP) and pptp (GRE/IP), both routable across the internet on VPN concentrators. A remote peer sending a PPP payload shorter than 3 bytes triggers the read.\nAC:L - The trigger is fully deterministic and entirely attacker-controlled — emit one PPP frame with a zero-length or 1-2 byte payload; there is no race, no memory-layout requirement, and no state the attacker cannot influence.\nPR:N - PPPoE/PPTP/L2TP session establishment happens before any PPP-layer authentication (LCP/CHAP/PAP), so the malformed frame can be sent by an unauthenticated peer on an established but not-yet-authenticated session. No local account or capability is needed.\nUI:N - The out-of-bounds read occurs during normal packet transmit processing driven entirely by the attacker's inbound frame. No victim action is required.\nS:U - The impact is confined to the kernel's own security authority — a kernel-memory read within the same host. No VM, IOMMU, or sandbox boundary is crossed.\nC:L - The read is strictly bounded to at most 3 bytes past the valid skb data, and those bytes are never transmitted — they only influence the `islcp`/protocol-compression branches, giving an indirect oracle over adjacent (possibly uninitialized) kernel heap contents rather than an arbitrary read primitive.\nI:N - The defect is read-only; `skb_pull()` is length-checked via `skb_pull_inline()` so `skb->len` cannot underflow, and the subsequent `skb_push()` is guarded by an explicit `skb_headroom()` check, leaving no out-of-bounds write or corrupted state.\nA:H - The out-of-bounds access is syzbot-reproducible and trips KASAN/KMSAN, causing an oops or panic on sanitizer-enabled and hardened kernels (panic_on_oops/panic_on_warn), and it can be triggered repeatedly by an unauthenticated remote peer."}]}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/net/ppp/ppp_synctty.c"],"versions":[{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","lessThan":"529401c8f12ecc35f9ea5d946d5a5596cf172b48","status":"affected","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","lessThan":"de5a4f0cba58625e88b7bebd88f780c8c0150997","status":"affected","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","lessThan":"99aa698dec342a07125d733e39aab4394b3b7e05","status":"affected","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","lessThan":"b78f2b458f56a5a4d976c8e01c43dbf58d3ea2ca","status":"affected","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","lessThan":"fbaffe8bccf148ece8ad67eb5d7aa852cabf59c8","status":"affected","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","lessThan":"b4c836d33ca888695b2f2665f948bc1b34fbd533","status":"affected","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","lessThan":"1f6eb9fa87a781d5370c0de7794ae242f1a95ee5","status":"affected","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","lessThan":"6e8a6bf43cea4347121ab21bb1ed8d7bef7e732e","status":"affected","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","lessThan":"aabc6596ffb377c4c9c8f335124b92ea282c9821","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/ppp_synctty.c"],"versions":[{"version":"2.6.12","status":"affected"},{"version":"0","lessThan":"2.6.12","status":"unaffected","versionType":"semver"},{"version":"5.4.293","lessThanOrEqual":"5.4.*","status":"unaffected","versionType":"semver"},{"version":"5.10.237","lessThanOrEqual":"5.10.*","status":"unaffected","versionType":"semver"},{"version":"5.15.181","lessThanOrEqual":"5.15.*","status":"unaffected","versionType":"semver"},{"version":"6.1.135","lessThanOrEqual":"6.1.*","status":"unaffected","versionType":"semver"},{"version":"6.6.88","lessThanOrEqual":"6.6.*","status":"unaffected","versionType":"semver"},{"version":"6.12.24","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.13.12","lessThanOrEqual":"6.13.*","status":"unaffected","versionType":"semver"},{"version":"6.14.3","lessThanOrEqual":"6.14.*","status":"unaffected","versionType":"semver"},{"version":"6.15","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":"5.4.293"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.12","versionEndExcluding":"5.10.237"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.12","versionEndExcluding":"5.15.181"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.12","versionEndExcluding":"6.1.135"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.12","versionEndExcluding":"6.6.88"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.12","versionEndExcluding":"6.12.24"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.12","versionEndExcluding":"6.13.12"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.12","versionEndExcluding":"6.14.3"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.12","versionEndExcluding":"6.15"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/529401c8f12ecc35f9ea5d946d5a5596cf172b48"},{"url":"https://git.kernel.org/stable/c/de5a4f0cba58625e88b7bebd88f780c8c0150997"},{"url":"https://git.kernel.org/stable/c/99aa698dec342a07125d733e39aab4394b3b7e05"},{"url":"https://git.kernel.org/stable/c/b78f2b458f56a5a4d976c8e01c43dbf58d3ea2ca"},{"url":"https://git.kernel.org/stable/c/fbaffe8bccf148ece8ad67eb5d7aa852cabf59c8"},{"url":"https://git.kernel.org/stable/c/b4c836d33ca888695b2f2665f948bc1b34fbd533"},{"url":"https://git.kernel.org/stable/c/1f6eb9fa87a781d5370c0de7794ae242f1a95ee5"},{"url":"https://git.kernel.org/stable/c/6e8a6bf43cea4347121ab21bb1ed8d7bef7e732e"},{"url":"https://git.kernel.org/stable/c/aabc6596ffb377c4c9c8f335124b92ea282c9821"}],"title":"net: ppp: Add bound checking for skb data on ppp_sync_txmung","x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"CVE Program Container","references":[{"url":"https://lists.debian.org/debian-lts-announce/2025/05/msg00045.html"},{"url":"https://lists.debian.org/debian-lts-announce/2025/05/msg00030.html"}],"providerMetadata":{"orgId":"af854a3a-2127-422b-91ae-364da2661108","shortName":"CVE","dateUpdated":"2025-11-03T19:54:24.795Z"}}]}}