{"api_version":"1","generated_at":"2026-10-07T11:05:49+00:00","cve":"CVE-2026-74735","urls":{"html":"https://cve.report/CVE-2026-74735","api":"https://cve.report/api/cve/CVE-2026-74735.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-74735","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-74735"},"summary":{"title":"l2tp: fix tunnel and session refcount leak on seq_file release","description":"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.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-08-26 15:16:52","updated_at":"2026-09-21 14:17:20"},"problem_types":[],"metrics":[],"references":[{"url":"https://git.kernel.org/stable/c/9006c116dd111d457bf5d074990210f70a4ad2c8","name":"https://git.kernel.org/stable/c/9006c116dd111d457bf5d074990210f70a4ad2c8","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/ebe2774e956482dd3c70b8991f6f7654356339e6","name":"https://git.kernel.org/stable/c/ebe2774e956482dd3c70b8991f6f7654356339e6","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/bdf83613781956cc39798ed08321f74ab0467f4d","name":"https://git.kernel.org/stable/c/bdf83613781956cc39798ed08321f74ab0467f4d","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/8c4fde01bcf91f22b9c7ded8c3e14addd7ddd500","name":"https://git.kernel.org/stable/c/8c4fde01bcf91f22b9c7ded8c3e14addd7ddd500","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-74735","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-74735","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 0e0c3fee3a59a387aeecc4fca6f3a2e9615a5443 bdf83613781956cc39798ed08321f74ab0467f4d git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 0e0c3fee3a59a387aeecc4fca6f3a2e9615a5443 8c4fde01bcf91f22b9c7ded8c3e14addd7ddd500 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 0e0c3fee3a59a387aeecc4fca6f3a2e9615a5443 ebe2774e956482dd3c70b8991f6f7654356339e6 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 0e0c3fee3a59a387aeecc4fca6f3a2e9615a5443 9006c116dd111d457bf5d074990210f70a4ad2c8 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected f6104e9ae04462523c372928b1173766a771ef95 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 7f8e401f9e612df2a95c1ef76217c00181389bb5 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected c712ed63e9b33d9a282fbd92ce25c64918c3129f git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 9a8863e8a8def9d88583cd9c60db38a008e6b8cf git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 3.16.60 3.17 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 4.16.6 4.17 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 4.17","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 4.17 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12.111 6.12.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.53 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.1.10 7.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.2 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"74735","cve":"CVE-2026-74735","epss":"0.001750000","percentile":"0.073000000","score_date":"2026-09-22","updated_at":"2026-09-23 00:06:34"},"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"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":"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":"6.12.*","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"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.12.111","versionStartIncluding":"4.17","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.53","versionStartIncluding":"4.17","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.1.10","versionStartIncluding":"4.17","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.2","versionStartIncluding":"4.17","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.16.60","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.16.6","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.16.60","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.16.6","vulnerable":true}],"negate":false,"operator":"OR"}]}],"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."}],"providerMetadata":{"dateUpdated":"2026-09-21T13:14:07.716Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/bdf83613781956cc39798ed08321f74ab0467f4d"},{"url":"https://git.kernel.org/stable/c/8c4fde01bcf91f22b9c7ded8c3e14addd7ddd500"},{"url":"https://git.kernel.org/stable/c/ebe2774e956482dd3c70b8991f6f7654356339e6"},{"url":"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"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-74735","datePublished":"2026-08-26T14:36:49.352Z","dateReserved":"2026-08-15T05:44:03.930Z","dateUpdated":"2026-09-21T13:14:07.716Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-08-26 15:16:52","lastModifiedDate":"2026-09-21 14:17:20","problem_types":[],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"74735","Ordinal":"1","Title":"l2tp: fix tunnel and session refcount leak on seq_file release","CVE":"CVE-2026-74735","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"74735","Ordinal":"1","NoteData":"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.","Type":"Description","Title":"l2tp: fix tunnel and session refcount leak on seq_file release"}]}}}