{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-68123", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-07-30T09:28:09.369Z", "datePublished": "2026-08-10T11:58:43.727Z", "dateUpdated": "2026-10-19T20:58:51.936Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-19T16:29:34.391Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nopenvswitch: fix GSO userspace truncation underflow\n\nOVS_ACTION_ATTR_TRUNC currently stores a delta from the original skb\nlength in OVS_CB(skb)->cutlen. When a later userspace action segments a\nGSO skb, queue_gso_packets() reuses that delta for each smaller segment.\nA segment can then reach queue_userspace_packet() with cutlen greater\nthan skb->len, underflowing the length passed to skb_zerocopy().\n\nStore the maximum preserved length instead and bound each consumer\nagainst the current skb length. Use U32_MAX as the no-truncation\nsentinel so the value remains valid if skb geometry changes before a\nconsumer handles it." } ], "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 - Ingress packets reach ovs_vport_receive() through netdev rx_handlers or tunnel vports; GRO-coalesced GSO skbs from remote senders traverse this path into queue_gso_packets(), so the underflow is reachable from the network without physical access.\nAC:L - The attacker chooses truncation max_len relative to GSO super-skb size and sends traffic that GRO segments predictably; no timing race or fragile heap layout is required to make cutlen exceed a child segment length after __skb_gso_segment().\nPR:N - In multi-tenant cloud/OVN deployments, a remote VM or container can send crafted GSO traffic into the host OVS datapath to hit provider-installed TRUNC+USERSPACE sampling flows without possessing any Linux capabilities on the host.\nUI:N - Triggering the flaw requires only network traffic matching existing OVS flow actions; no victim login, file open, mount, or other interactive step is needed.\nS:U - Impact is kernel memory corruption and crash/escalation within the host kernel security domain; it does not cross a guest-to-hypervisor, VM, or hardware IOMMU trust boundary by itself.\nC:H - Unsigned underflow makes skb->len-cutlen enormous for skb_zerocopy()/skb_copy_bits(), enabling out-of-bounds reads from the source skb and adjacent slab data, i.e., an exploitable information-disclosure primitive.\nI:H - The same underflowed length can expand destination skbs via skb_len_add()/nlattr sizing, corrupting kernel heap metadata and yielding a write primitive suitable for control-flow hijacking.\nA:H - The miscopied lengths can BUG the skb helpers or cause immediate kernel oops/panic during zerocopy/trim handling, and corrupted metadata can crash the system even if exploitation is not completed." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/openvswitch/actions.c", "net/openvswitch/datapath.c", "net/openvswitch/datapath.h", "net/openvswitch/vport.c" ], "versions": [ { "version": "f2a4d086ed4c588d32fe9b7aa67fead7280e7bf1", "lessThan": "50a6a85f3d6b1d22d8436848606cdef5d2c490b4", "status": "affected", "versionType": "git" }, { "version": "f2a4d086ed4c588d32fe9b7aa67fead7280e7bf1", "lessThan": "2623c48cc3a8da9a1886fd8f65c0e348f4406fd6", "status": "affected", "versionType": "git" }, { "version": "f2a4d086ed4c588d32fe9b7aa67fead7280e7bf1", "lessThan": "e211b081901ffca76674082c73eeaed53524c369", "status": "affected", "versionType": "git" }, { "version": "f2a4d086ed4c588d32fe9b7aa67fead7280e7bf1", "lessThan": "a16eaaf7c0b0ccdef6166707d90ffbc6eebf6855", "status": "affected", "versionType": "git" }, { "version": "f2a4d086ed4c588d32fe9b7aa67fead7280e7bf1", "lessThan": "fbfa3ad2ad6f3a5624aba5211c46290fb98cc9dc", "status": "affected", "versionType": "git" }, { "version": "f2a4d086ed4c588d32fe9b7aa67fead7280e7bf1", "lessThan": "100a23b1613e9218e0af654ef102352c713f0263", "status": "affected", "versionType": "git" }, { "version": "f2a4d086ed4c588d32fe9b7aa67fead7280e7bf1", "lessThan": "ea85dbcbe8d4056ecb54352f97743d138ea4c407", "status": "affected", "versionType": "git" }, { "version": "f2a4d086ed4c588d32fe9b7aa67fead7280e7bf1", "lessThan": "4032f8ed10fcb84d41c508dfb04be96589f78dfe", "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/openvswitch/actions.c", "net/openvswitch/datapath.c", "net/openvswitch/datapath.h", "net/openvswitch/vport.c" ], "versions": [ { "version": "4.8", "status": "affected" }, { "version": "0", "lessThan": "4.8", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.265", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.216", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.183", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.148", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.101", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.42", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.1.6", "lessThanOrEqual": "7.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2", "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": "4.8", "versionEndExcluding": "5.10.265" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.8", "versionEndExcluding": "5.15.216" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.8", "versionEndExcluding": "6.1.183" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.8", "versionEndExcluding": "6.6.148" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.8", "versionEndExcluding": "6.12.101" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.8", "versionEndExcluding": "6.18.42" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.8", "versionEndExcluding": "7.1.6" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.8", "versionEndExcluding": "7.2" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/50a6a85f3d6b1d22d8436848606cdef5d2c490b4" }, { "url": "https://git.kernel.org/stable/c/2623c48cc3a8da9a1886fd8f65c0e348f4406fd6" }, { "url": "https://git.kernel.org/stable/c/e211b081901ffca76674082c73eeaed53524c369" }, { "url": "https://git.kernel.org/stable/c/a16eaaf7c0b0ccdef6166707d90ffbc6eebf6855" }, { "url": "https://git.kernel.org/stable/c/fbfa3ad2ad6f3a5624aba5211c46290fb98cc9dc" }, { "url": "https://git.kernel.org/stable/c/100a23b1613e9218e0af654ef102352c713f0263" }, { "url": "https://git.kernel.org/stable/c/ea85dbcbe8d4056ecb54352f97743d138ea4c407" }, { "url": "https://git.kernel.org/stable/c/4032f8ed10fcb84d41c508dfb04be96589f78dfe" } ], "title": "openvswitch: fix GSO userspace truncation underflow", "x_generator": { "engine": "bippy-1.2.0" } }, "adp": [ { "metrics": [ { "other": { "type": "ssvc", "content": { "id": "CVE-2026-68123", "role": "CISA Coordinator", "options": [ { "Exploitation": "none" }, { "Automatable": "yes" }, { "Technical Impact": "total" } ], "version": "2.0.3", "timestamp": "2026-10-16T15:44:13.520896Z" } } } ], "problemTypes": [ { "descriptions": [ { "lang": "en", "type": "CWE", "cweId": "CWE-191", "description": "CWE-191 Integer Underflow (Wrap or Wraparound)" } ] } ], "title": "CISA ADP Vulnrichment", "providerMetadata": { "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-10-19T20:58:51.936Z" } } ] } }