{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-63925", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-07-19T07:54:57.021Z", "datePublished": "2026-07-19T14:55:26.442Z", "dateUpdated": "2026-08-05T12:37:20.197Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:37:20.197Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmacsec: fix replay protection at XPN lower-PN wrap\n\nIn macsec_post_decrypt(), when pn is U32_MAX, pn + 1 overflows u32 to 0\nand the first branch never fires. If next_pn_halves.lower is also in the\nupper half, pn_same_half(pn, lower) is true and the XPN else-if does not\nfire either, leaving next_pn_halves unchanged. An attacker that captures\nthe legitimate frame carrying pn == 0xFFFFFFFF on an XPN association\ncan then replay it indefinitely, since lowest_pn never rises above\nthe captured pn and macsec_decrypt() reconstructs the same IV.\n\nExtend the XPN else-if to also fire when pn + 1 wraps to 0, so receipt\nof pn == U32_MAX advances next_pn_halves to (upper + 1, 0)." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H", "baseScore": 8.1, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:A - MACsec processes attacker-supplied Ethernet frames via netdev rx_handler on the underlying link; exploitation requires L2 adjacency on the same broadcast domain or point-to-point MACsec link, not remote Internet reachability.\nAC:L - Once XPN with replay protection is deployed, an on-link attacker can passively capture the single legitimate frame at PN 0xFFFFFFFF and then replay it reliably and indefinitely without races or conditions outside their control.\nPR:N - Exploitation requires only the ability to send or replay Ethernet frames on the MACsec link; no local privileges, capabilities, or authentication on the victim Linux host are needed.\nUI:N - Replay injection is fully attacker-driven after capturing the target frame; no victim user or administrator action is required during exploitation.\nS:U - The flaw bypasses MACsec replay protection within the kernel network stack and does not cross a security boundary such as a VM, container, or IOMMU isolation domain.\nC:N - This is a replay-protection logic flaw, not a memory corruption or decryption weakness; the attacker replays already-captured ciphertext and gains no new confidentiality beyond what passive capture already provided.\nI:H - Bypassing replay protection allows unlimited re-injection of previously authenticated payloads into the controlled port, defeating MACsec's integrity guarantees and enabling repeated delivery of captured control or data traffic on automotive, industrial, and datacenter MACsec links.\nA:H - The commit confirms captured frames can be replayed indefinitely, enabling sustained injection of decrypted traffic that can overwhelm the receiver and deny service to legitimate peers on the protected link." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/net/macsec.c" ], "versions": [ { "version": "a21ecf0e033807b976967286e6c392f48ee2049f", "lessThan": "dd7306779c6ce1238f4cdc34f3c1f2246b854457", "status": "affected", "versionType": "git" }, { "version": "a21ecf0e033807b976967286e6c392f48ee2049f", "lessThan": "d15130461df388136b62a7b0ce9f66e7e2fa9ff1", "status": "affected", "versionType": "git" }, { "version": "a21ecf0e033807b976967286e6c392f48ee2049f", "lessThan": "23c0e230eab397d7f68be2538790ac41d3bb91fd", "status": "affected", "versionType": "git" }, { "version": "a21ecf0e033807b976967286e6c392f48ee2049f", "lessThan": "679e13a65e68a67c8b3c0467c02ee89157ec6f0f", "status": "affected", "versionType": "git" }, { "version": "a21ecf0e033807b976967286e6c392f48ee2049f", "lessThan": "79495a1b0944fe31ffd54b54b00211b493590d62", "status": "affected", "versionType": "git" }, { "version": "a21ecf0e033807b976967286e6c392f48ee2049f", "lessThan": "6d00f5c7e5ff7ec4795b7f5f8ed88bd346641652", "status": "affected", "versionType": "git" }, { "version": "a21ecf0e033807b976967286e6c392f48ee2049f", "lessThan": "d55acbe577db892b60547b6ef1c020b359331a6d", "status": "affected", "versionType": "git" }, { "version": "a21ecf0e033807b976967286e6c392f48ee2049f", "lessThan": "e68842b3356471ba56c882209f324613dac47f64", "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/macsec.c" ], "versions": [ { "version": "5.7", "status": "affected" }, { "version": "0", "lessThan": "5.7", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.259", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.210", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.176", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.143", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.93", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.35", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.0.12", "lessThanOrEqual": "7.0.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.1", "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": "5.7", "versionEndExcluding": "5.10.259" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.7", "versionEndExcluding": "5.15.210" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.7", "versionEndExcluding": "6.1.176" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.7", "versionEndExcluding": "6.6.143" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.7", "versionEndExcluding": "6.12.93" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.7", "versionEndExcluding": "6.18.35" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.7", "versionEndExcluding": "7.0.12" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.7", "versionEndExcluding": "7.1" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/dd7306779c6ce1238f4cdc34f3c1f2246b854457" }, { "url": "https://git.kernel.org/stable/c/d15130461df388136b62a7b0ce9f66e7e2fa9ff1" }, { "url": "https://git.kernel.org/stable/c/23c0e230eab397d7f68be2538790ac41d3bb91fd" }, { "url": "https://git.kernel.org/stable/c/679e13a65e68a67c8b3c0467c02ee89157ec6f0f" }, { "url": "https://git.kernel.org/stable/c/79495a1b0944fe31ffd54b54b00211b493590d62" }, { "url": "https://git.kernel.org/stable/c/6d00f5c7e5ff7ec4795b7f5f8ed88bd346641652" }, { "url": "https://git.kernel.org/stable/c/d55acbe577db892b60547b6ef1c020b359331a6d" }, { "url": "https://git.kernel.org/stable/c/e68842b3356471ba56c882209f324613dac47f64" } ], "title": "macsec: fix replay protection at XPN lower-PN wrap", "x_generator": { "engine": "bippy-1.2.0" } } } }