{"id":"CVE-2026-68293","state":"PUBLISHED","title":"net/mlx5: Fix MCIA register buffer overflow on 32 dword reads","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet/mlx5: Fix MCIA register buffer overflow on 32 dword reads\n\nThe MCIA register can return up to 32 dwords (128 bytes) when the device\nadvertises the mcia_32dwords capability, but struct\nmlx5_ifc_mcia_reg_bits only defines dword_0..11, leaving room for just\n12 dwords (48 bytes) of data.\n\nmlx5_query_mcia() clamps the read size to mlx5_mcia_max_bytes() and then\nmemcpy()s that many bytes out of the register, potentially reading past\nthe end of the 'out' buffer. On kernels built with FORTIFY_SOURCE this\nis caught as a buffer overflow while reading the module EEPROM via\nethtool:\n\n  detected buffer overflow in memcpy\n  kernel BUG at lib/string_helpers.c:1048!\n  RIP: 0010:fortify_panic+0x13/0x20\n  Call Trace:\n   mlx5_query_mcia.isra.0+0x200/0x210 [mlx5_core]\n   mlx5_query_module_eeprom_by_page+0x4a/0xa0 [mlx5_core]\n   mlx5e_get_module_eeprom_by_page+0xbb/0x120 [mlx5_core]\n   eeprom_prepare_data+0xf3/0x170\n   ethnl_default_doit+0xf1/0x3b0\n\nExtend the mcia_reg layout to 32 dwords.","publishedAt":"2026-08-10T12:02:26.414Z","updatedAt":"2026-10-30T12:28:20.185Z","severity":{"score":7.1,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"271907ee2f29cd1078fd219f0778fd824fb1971c","status":"affected","lessThan":"5ed6d41029832b11bc204d7cc326cf309d073666","versionType":"git"},{"version":"271907ee2f29cd1078fd219f0778fd824fb1971c","status":"affected","lessThan":"c8a4acc19dcdc83e1303c29d9535e5c99415a2e3","versionType":"git"},{"version":"271907ee2f29cd1078fd219f0778fd824fb1971c","status":"affected","lessThan":"5be4eebd5a3a198dab0adcd550e1cadca79bdfed","versionType":"git"},{"version":"271907ee2f29cd1078fd219f0778fd824fb1971c","status":"affected","lessThan":"87b39a8c875ca744b7de69af0a8ef8874cffccf1","versionType":"git"},{"version":"271907ee2f29cd1078fd219f0778fd824fb1971c","status":"affected","lessThan":"88b2a16ddac3357e3f1d528e758b51e2c945d546","versionType":"git"},{"version":"271907ee2f29cd1078fd219f0778fd824fb1971c","status":"affected","lessThan":"11c057d23465c7a5817a7284c896d19d54c0b616","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/net/ethernet/mellanox/mlx5/core/port.c","include/linux/mlx5/mlx5_ifc.h"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.18","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.18","versionType":"semver"},{"version":"6.1.191","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.160","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.101","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.42","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.6","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/net/ethernet/mellanox/mlx5/core/port.c","include/linux/mlx5/mlx5_ifc.h"]}],"references":["https://git.kernel.org/stable/c/5ed6d41029832b11bc204d7cc326cf309d073666","https://git.kernel.org/stable/c/c8a4acc19dcdc83e1303c29d9535e5c99415a2e3","https://git.kernel.org/stable/c/5be4eebd5a3a198dab0adcd550e1cadca79bdfed","https://git.kernel.org/stable/c/87b39a8c875ca744b7de69af0a8ef8874cffccf1","https://git.kernel.org/stable/c/88b2a16ddac3357e3f1d528e758b51e2c945d546","https://git.kernel.org/stable/c/11c057d23465c7a5817a7284c896d19d54c0b616"],"weaknesses":["CWE-122"],"ingestedAt":"2026-10-30T12:46:06.359Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/68xxx/CVE-2026-68293.json","commit":"1f312381e38164a43607eebab851b151dd16861e","baselineCommit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-68293","state":"PUBLISHED","datePublished":"2026-08-10T12:02:26.414Z","dateUpdated":"2026-10-30T12:28:20.185Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-07-30T09:28:09.380Z"},"containers":{"cna":{"title":"net/mlx5: Fix MCIA register buffer overflow on 32 dword reads","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet/mlx5: Fix MCIA register buffer overflow on 32 dword reads\n\nThe MCIA register can return up to 32 dwords (128 bytes) when the device\nadvertises the mcia_32dwords capability, but struct\nmlx5_ifc_mcia_reg_bits only defines dword_0..11, leaving room for just\n12 dwords (48 bytes) of data.\n\nmlx5_query_mcia() clamps the read size to mlx5_mcia_max_bytes() and then\nmemcpy()s that many bytes out of the register, potentially reading past\nthe end of the 'out' buffer. On kernels built with FORTIFY_SOURCE this\nis caught as a buffer overflow while reading the module EEPROM via\nethtool:\n\n  detected buffer overflow in memcpy\n  kernel BUG at lib/string_helpers.c:1048!\n  RIP: 0010:fortify_panic+0x13/0x20\n  Call Trace:\n   mlx5_query_mcia.isra.0+0x200/0x210 [mlx5_core]\n   mlx5_query_module_eeprom_by_page+0x4a/0xa0 [mlx5_core]\n   mlx5e_get_module_eeprom_by_page+0xbb/0x120 [mlx5_core]\n   eeprom_prepare_data+0xf3/0x170\n   ethnl_default_doit+0xf1/0x3b0\n\nExtend the mcia_reg layout to 32 dwords."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"271907ee2f29cd1078fd219f0778fd824fb1971c","status":"affected","lessThan":"5ed6d41029832b11bc204d7cc326cf309d073666","versionType":"git"},{"version":"271907ee2f29cd1078fd219f0778fd824fb1971c","status":"affected","lessThan":"c8a4acc19dcdc83e1303c29d9535e5c99415a2e3","versionType":"git"},{"version":"271907ee2f29cd1078fd219f0778fd824fb1971c","status":"affected","lessThan":"5be4eebd5a3a198dab0adcd550e1cadca79bdfed","versionType":"git"},{"version":"271907ee2f29cd1078fd219f0778fd824fb1971c","status":"affected","lessThan":"87b39a8c875ca744b7de69af0a8ef8874cffccf1","versionType":"git"},{"version":"271907ee2f29cd1078fd219f0778fd824fb1971c","status":"affected","lessThan":"88b2a16ddac3357e3f1d528e758b51e2c945d546","versionType":"git"},{"version":"271907ee2f29cd1078fd219f0778fd824fb1971c","status":"affected","lessThan":"11c057d23465c7a5817a7284c896d19d54c0b616","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/net/ethernet/mellanox/mlx5/core/port.c","include/linux/mlx5/mlx5_ifc.h"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.18","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.18","versionType":"semver"},{"version":"6.1.191","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.160","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.101","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.42","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.6","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/net/ethernet/mellanox/mlx5/core/port.c","include/linux/mlx5/mlx5_ifc.h"]}],"references":[{"url":"https://git.kernel.org/stable/c/5ed6d41029832b11bc204d7cc326cf309d073666"},{"url":"https://git.kernel.org/stable/c/c8a4acc19dcdc83e1303c29d9535e5c99415a2e3"},{"url":"https://git.kernel.org/stable/c/5be4eebd5a3a198dab0adcd550e1cadca79bdfed"},{"url":"https://git.kernel.org/stable/c/87b39a8c875ca744b7de69af0a8ef8874cffccf1"},{"url":"https://git.kernel.org/stable/c/88b2a16ddac3357e3f1d528e758b51e2c945d546"},{"url":"https://git.kernel.org/stable/c/11c057d23465c7a5817a7284c896d19d54c0b616"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H","baseScore":7.1,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:L - The bug is reached only through local ethtool interfaces on the mlx5 netdev — the ETHTOOL_MSG_MODULE_EEPROM_GET genetlink message or the ETHTOOL_GMODULEEEPROM ioctl on a socket. No remote peer or received packet can trigger it.\nAC:L - A single ethtool module-EEPROM read of 128 bytes deterministically triggers the over-read on any adapter whose firmware advertises mcia_32dwords, which is the normal case on modern ConnectX hardware with a transceiver installed. No race, no memory-layout grooming, fully repeatable.\nPR:L - Both entry points check ns_capable(net->user_ns, CAP_NET_ADMIN), which is namespace-relative, so the root of an unprivileged user namespace owning a netns that holds an mlx5 VF/subfunction netdev (a standard SR-IOV container setup) can trigger it without any privilege in the initial namespace.\nUI:N - The attacker triggers the read entirely on their own by issuing an ethtool query; no action by another user or administrator is needed.\nS:U - The out-of-bounds read and its consequences are confined to the kernel of the same host; no VM, IOMMU, or other security-authority boundary is crossed.\nC:H - Up to 80 bytes of kernel stack adjacent to the 64-byte 'out' buffer are memcpy()'d into the EEPROM data returned to userspace, disclosing saved registers, pointers and potentially return addresses or the stack canary — enough to defeat KASLR and stack protection and aid further exploitation.\nI:N - The defect is purely a read overflow; the destination buffer is sized from the caller's own request length, so no kernel memory is written out of bounds and no data is modified.\nA:H - On the widely enabled CONFIG_FORTIFY_SOURCE the copy hits fortify_panic(), producing a kernel BUG/oops in mlx5_query_mcia() while rtnl/netdev locks are held (per the reported trace), wedging networking and panicking outright with panic_on_oops."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-30T12:28:20.185Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.18","versionEndExcluding":"6.1.191"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.18","versionEndExcluding":"6.6.160"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.18","versionEndExcluding":"6.12.101"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.18","versionEndExcluding":"6.18.42"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.18","versionEndExcluding":"7.1.6"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.18","versionEndExcluding":"7.2"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2026-68293","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"version":"2.0.3","timestamp":"2026-10-16T15:46:41.032744Z"}}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-122","lang":"en","type":"CWE","description":"CWE-122 Heap-based Buffer Overflow"}]}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-10-19T21:09:03.453Z"}}]}}}