CVE-2026-74735

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-74735", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-08-15T05:44:03.930Z", "datePublished": "2026-08-26T14:36:49.352Z", "dateUpdated": "2026-10-30T12:30:27.082Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-30T12:30:27.082Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nl2tp: fix tunnel and session refcount leak on seq_file release\n\nIn pppol2tp_proc_open() and l2tp_dfs_seq_open(), iteration state\n(pd->tunnel and pd->session) is kept in seq_file private data to allow\niteration across multiple read() system calls.\n\nHowever, if userspace closes /proc/net/pppol2tp or /sys/kernel/debug/l2tp/tunnels\nbefore reading to end-of-file (EOF), any tunnel or session reference stored in\npd->tunnel / pd->session is left un-dropped when seq_file private data is freed.\n\nFix this by dropping any remaining pd->tunnel and pd->session references in\npppol2tp_proc_release() and l2tp_dfs_seq_release() when closing the file."}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["net/l2tp/l2tp_debugfs.c", "net/l2tp/l2tp_ppp.c"], "versions": [{"version": "0e0c3fee3a59a387aeecc4fca6f3a2e9615a5443", "lessThan": "c38b723858a51d6ca4e56470b9f1087f23276772", "status": "affected", "versionType": "git"}, {"version": "0e0c3fee3a59a387aeecc4fca6f3a2e9615a5443", "lessThan": "bd897e414451fb34dfdf08b31899180e5ab7149b", "status": "affected", "versionType": "git"}, {"version": "0e0c3fee3a59a387aeecc4fca6f3a2e9615a5443", "lessThan": "bdf83613781956cc39798ed08321f74ab0467f4d", "status": "affected", "versionType": "git"}, {"version": "0e0c3fee3a59a387aeecc4fca6f3a2e9615a5443", "lessThan": "8c4fde01bcf91f22b9c7ded8c3e14addd7ddd500", "status": "affected", "versionType": "git"}, {"version": "0e0c3fee3a59a387aeecc4fca6f3a2e9615a5443", "lessThan": "ebe2774e956482dd3c70b8991f6f7654356339e6", "status": "affected", "versionType": "git"}, {"version": "0e0c3fee3a59a387aeecc4fca6f3a2e9615a5443", "lessThan": "9006c116dd111d457bf5d074990210f70a4ad2c8", "status": "affected", "versionType": "git"}, {"version": "f6104e9ae04462523c372928b1173766a771ef95", "status": "affected", "versionType": "git"}, {"version": "7f8e401f9e612df2a95c1ef76217c00181389bb5", "status": "affected", "versionType": "git"}, {"version": "c712ed63e9b33d9a282fbd92ce25c64918c3129f", "status": "affected", "versionType": "git"}, {"version": "9a8863e8a8def9d88583cd9c60db38a008e6b8cf", "status": "affected", "versionType": "git"}, {"version": "3.16.60", "lessThan": "3.17", "status": "affected", "versionType": "semver"}, {"version": "4.16.6", "lessThan": "4.17", 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"original_commit_for_fix"}]}], "cpeApplicability": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.17", "versionEndExcluding": "6.1.191"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.17", "versionEndExcluding": "6.6.160"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.17", "versionEndExcluding": "6.12.111"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.17", "versionEndExcluding": "6.18.53"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.17", "versionEndExcluding": "7.1.10"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.17", "versionEndExcluding": 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"https://git.kernel.org/stable/c/9006c116dd111d457bf5d074990210f70a4ad2c8"}], "title": "l2tp: fix tunnel and session refcount leak on seq_file release", "x_generator": {"engine": "bippy-1.2.0"}}}}

{}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Linux", "programFiles": ["net/l2tp/l2tp_debugfs.c", "net/l2tp/l2tp_ppp.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"lessThan": "c38b723858a51d6ca4e56470b9f1087f23276772", "status": "affected", "version": "0e0c3fee3a59a387aeecc4fca6f3a2e9615a5443", "versionType": "git"}, {"lessThan": "bd897e414451fb34dfdf08b31899180e5ab7149b", "status": "affected", "version": "0e0c3fee3a59a387aeecc4fca6f3a2e9615a5443", "versionType": "git"}, {"lessThan": "bdf83613781956cc39798ed08321f74ab0467f4d", "status": "affected", "version": "0e0c3fee3a59a387aeecc4fca6f3a2e9615a5443", "versionType": "git"}, {"lessThan": "8c4fde01bcf91f22b9c7ded8c3e14addd7ddd500", "status": "affected", "version": "0e0c3fee3a59a387aeecc4fca6f3a2e9615a5443", "versionType": "git"}, {"lessThan": "ebe2774e956482dd3c70b8991f6f7654356339e6", "status": "affected", "version": "0e0c3fee3a59a387aeecc4fca6f3a2e9615a5443", "versionType": "git"}, {"lessThan": "9006c116dd111d457bf5d074990210f70a4ad2c8", "status": "affected", "version": "0e0c3fee3a59a387aeecc4fca6f3a2e9615a5443", "versionType": "git"}, {"status": "affected", "version": "f6104e9ae04462523c372928b1173766a771ef95", "versionType": "git"}, {"status": "affected", "version": "7f8e401f9e612df2a95c1ef76217c00181389bb5", "versionType": "git"}, {"status": "affected", "version": "c712ed63e9b33d9a282fbd92ce25c64918c3129f", "versionType": "git"}, {"status": "affected", "version": "9a8863e8a8def9d88583cd9c60db38a008e6b8cf", "versionType": "git"}, {"lessThan": "3.17", "status": "affected", "version": "3.16.60", "versionType": "semver"}, {"lessThan": "4.17", "status": "affected", "version": "4.16.6", "versionType": "semver"}]}, {"defaultStatus": "affected", "product": "Linux", "programFiles": ["net/l2tp/l2tp_debugfs.c", "net/l2tp/l2tp_ppp.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"status": "affected", "version": "4.17"}, {"lessThan": "4.17", "status": "unaffected", "version": "0", "versionType": "semver"}, {"lessThanOrEqual": "6.1.*", "status": "unaffected", "version": "6.1.191", "versionType": "semver"}, {"lessThanOrEqual": "6.6.*", "status": "unaffected", "version": "6.6.160", "versionType": "semver"}, {"lessThanOrEqual": "6.12.*", "status": "unaffected", "version": "6.12.111", "versionType": "semver"}, {"lessThanOrEqual": "6.18.*", "status": "unaffected", "version": "6.18.53", "versionType": "semver"}, {"lessThanOrEqual": "7.1.*", "status": "unaffected", "version": "7.1.10", "versionType": "semver"}, {"lessThanOrEqual": "*", "status": "unaffected", "version": "7.2", "versionType": "original_commit_for_fix"}]}], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nl2tp: fix tunnel and session refcount leak on seq_file release\n\nIn pppol2tp_proc_open() and l2tp_dfs_seq_open(), iteration state\n(pd->tunnel and pd->session) is kept in seq_file private data to allow\niteration across multiple read() system calls.\n\nHowever, if userspace closes /proc/net/pppol2tp or /sys/kernel/debug/l2tp/tunnels\nbefore reading to end-of-file (EOF), any tunnel or session reference stored in\npd->tunnel / pd->session is left un-dropped when seq_file private data is freed.\n\nFix this by dropping any remaining pd->tunnel and pd->session references in\npppol2tp_proc_release() and l2tp_dfs_seq_release() when closing the file."}], "id": "CVE-2026-74735", "lastModified": "2026-10-30T13:20:05.277", "metrics": {}, "published": "2026-08-26T15:16:52.057", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/8c4fde01bcf91f22b9c7ded8c3e14addd7ddd500"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/9006c116dd111d457bf5d074990210f70a4ad2c8"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/bd897e414451fb34dfdf08b31899180e5ab7149b"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/bdf83613781956cc39798ed08321f74ab0467f4d"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/c38b723858a51d6ca4e56470b9f1087f23276772"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/ebe2774e956482dd3c70b8991f6f7654356339e6"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Received"}

{"bugzilla": {"description": "kernel: l2tp: fix tunnel and session refcount leak on seq_file release", "id": "2524484", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2524484"}, "csaw": false, "cvss3": {"cvss3_base_score": "5.5", "cvss3_scoring_vector": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H", "status": "draft"}, "cwe": "CWE-911", "details": ["In the Linux kernel, the following vulnerability has been resolved:\nl2tp: fix tunnel and session refcount leak on seq_file release\nIn pppol2tp_proc_open() and l2tp_dfs_seq_open(), iteration state\n(pd->tunnel and pd->session) is kept in seq_file private data to allow\niteration across multiple read() system calls.\nHowever, if userspace closes /proc/net/pppol2tp or /sys/kernel/debug/l2tp/tunnels\nbefore reading to end-of-file (EOF), any tunnel or session reference stored in\npd->tunnel / pd->session is left un-dropped when seq_file private data is freed.\nFix this by dropping any remaining pd->tunnel and pd->session references in\npppol2tp_proc_release() and l2tp_dfs_seq_release() when closing the file.", "A flaw was found in the Linux kernel's L2TP (Layer 2 Tunneling Protocol) implementation. A local user could trigger a reference count leak by closing specific `/proc` or `/sys` files related to L2TP tunnels and sessions before fully reading their content. This could lead to resource exhaustion, potentially causing a Denial of Service (DoS) condition on the system."], "name": "CVE-2026-74735", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Fix deferred", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Out of support scope", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Fix deferred", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Fix deferred", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Fix deferred", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Fix deferred", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Fix deferred", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Fix deferred", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 9"}], "public_date": "2026-08-26T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-74735\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-74735\nhttps://lore.kernel.org/linux-cve-announce/2026082656-CVE-2026-74735-e7ef@gregkh/T"], "threat_severity": "Moderate"}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[0e0c3fee3a59a387aeecc4fca6f3a2e9615a5443,ebe2774e956482dd3c70b8991f6f7654356339e6)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[0e0c3fee3a59a387aeecc4fca6f3a2e9615a5443,9006c116dd111d457bf5d074990210f70a4ad2c8)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "f6104e9ae04462523c372928b1173766a771ef95"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "7f8e401f9e612df2a95c1ef76217c00181389bb5"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "c712ed63e9b33d9a282fbd92ce25c64918c3129f"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "9a8863e8a8def9d88583cd9c60db38a008e6b8cf"}}, {"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[3.16.60,3.17)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[4.16.6,4.17)"}}], "enrichment": {"confidence": 99.0, "confidence_source": "inferred", "scores": [{"score": 99.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}, {"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "generic", "value": "4.17"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[0,4.17)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[7.1.10,7.2.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[7.2,*]"}}], "enrichment": {"confidence": 99.0, "confidence_source": "inferred", "scores": [{"score": 99.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}], "created": "2026-08-26T16:00:07.218291+00:00", "updated": "2026-08-28T19:30:16.878047+00:00", "vendors": ["linux", "linux$PRODUCT$linux_kernel"]}