{"schema":"threatline.record/2","record":{"id":"CVE-2026-98840","aliases":[],"summary":"vc_screen: reload vc pointer before if (ret) in vcs_write() to avoid UAF","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nvc_screen: reload vc pointer before if (ret) in vcs_write() to avoid UAF\n\nThe reload of 'vc' added by commit 8fb9ea65c9d1 (\"vc_screen: reload load\nof struct vc_data pointer in vcs_write() to avoid UAF\") sits after the\n'if (ret)' block, so the copy-failure break path exits the loop without\nreloading vc. If the vc was kfree()'d via vc_port_destruct during the\nunlocked copy_from_user() window, the post-loop\n'if (written && vc) vcs_scr_updated(vc)' is reached with a stale\nnon-NULL vc. The '&& vc' guard from commit a287620312dc (\"vc_screen:\nfix null-ptr-deref in vcs_notifier() during concurrent vcs_write\") only\nhandles the NULL case, not this stale-non-NULL case; vcs_notifier() then\nreads param->vc->vc_num from freed memory:\n\n  BUG: KASAN: slab-use-after-free in vcs_notifier+0x7c/0xd0\n  Read of size 2 at addr ffff888007149190\n  Call Trace:\n   vcs_notifier+0x7c/0xd0\n   atomic_notifier_call_chain+0x70/0xa0\n   vcs_scr_updated+0x77/0xa0\n   vcs_write+0x71b/0x7e0\n  Allocated by task: vc_allocate -> con_install -> tty_open\n  Freed by task: kfree <- vt_ioctl (VT_DISALLOCATE -> vc_port_destruct)\n\nMove the reload to immediately after console_lock(), before 'if (ret)',\nso every break path below passes a fresh vc to the post-loop\nvcs_scr_updated().","categories":["Operating systems"],"product":"Linux","vendor":"Linux","ecosystem":null,"affected_ranges":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98840","source_modified_at":"2026-10-21T12:57:25.411Z","fetched_at":"2026-10-23T18:45:31.882637Z","product":"Linux","vendor":"Linux","versions":[{"version":"8232fca738011ca2ec865b46ec721d1796dc0580","lessThan":"c073d01f6f5367c3a4f07efd507274ed0d03acd0","status":"affected","versionType":"git"},{"version":"73049768ad57145acd337102c5aa3c788e6642c8","lessThan":"1485a3dd97ab1af2605243cabe6b604546d46dd1","status":"affected","versionType":"git"},{"version":"7cc3dd79777f6ae4625ec37e84dd18a26dc88bde","lessThan":"233a2e190b12884d186027d0b86d43a48799b69c","status":"affected","versionType":"git"},{"version":"a287620312dc6dcb9a093417a0e589bf30fcf38a","lessThan":"9dfcadc5e003fb250dd471db90144bd5366140e9","status":"affected","versionType":"git"},{"version":"a287620312dc6dcb9a093417a0e589bf30fcf38a","lessThan":"226bd5603371cd9f6642cbb9e9a677f445de3530","status":"affected","versionType":"git"},{"version":"43a6281790273c1b0a9ab76609ff0245b968f1e6","status":"affected","versionType":"git"},{"version":"b6bbb85cf45bf0b070e741997fe0af3a772c5ad5","status":"affected","versionType":"git"},{"version":"ff4806202749a51938236214adc0281481a57366","status":"affected","versionType":"git"},{"version":"74be188eb2dc1c99d63986167b9a67d415fe7326","status":"affected","versionType":"git"},{"version":"09a43e81279b8da15526da09877134b8bcf618b0","status":"affected","versionType":"git"},{"version":"6.6.144","lessThan":"6.6.160","status":"affected","versionType":"semver"},{"version":"6.12.95","lessThan":"6.12.113","status":"affected","versionType":"semver"},{"version":"6.18.37","lessThan":"6.18.56","status":"affected","versionType":"semver"},{"version":"5.10.260","lessThan":"5.11","status":"affected","versionType":"semver"},{"version":"5.15.211","lessThan":"5.16","status":"affected","versionType":"semver"},{"version":"6.1.177","lessThan":"6.2","status":"affected","versionType":"semver"},{"version":"7.0.14","lessThan":"7.1","status":"affected","versionType":"semver"},{"version":"7.1.2","lessThan":"7.2","status":"affected","versionType":"semver"}],"defaultStatus":"unaffected"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98840","source_modified_at":"2026-10-21T12:57:25.411Z","fetched_at":"2026-10-23T18:45:31.882637Z","product":"Linux","vendor":"Linux","versions":[{"version":"7.2","status":"affected"},{"version":"0","lessThan":"7.2","status":"unaffected","versionType":"semver"},{"version":"6.6.160","lessThanOrEqual":"6.6.*","status":"unaffected","versionType":"semver"},{"version":"6.12.113","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.18.56","lessThanOrEqual":"6.18.*","status":"unaffected","versionType":"semver"},{"version":"7.2.10","lessThanOrEqual":"7.2.*","status":"unaffected","versionType":"semver"},{"version":"7.3","lessThanOrEqual":"*","status":"unaffected","versionType":"original_commit_for_fix"}],"defaultStatus":"affected"}],"fixed_versions":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98840","source_modified_at":"2026-10-21T12:57:25.411Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"Linux","ecosystem":null},"version":"1485a3dd97ab1af2605243cabe6b604546d46dd1","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98840","source_modified_at":"2026-10-21T12:57:25.411Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"Linux","ecosystem":null},"version":"233a2e190b12884d186027d0b86d43a48799b69c","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98840","source_modified_at":"2026-10-21T12:57:25.411Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"Linux","ecosystem":null},"version":"9dfcadc5e003fb250dd471db90144bd5366140e9","basis":"first unaffected version stated in the CVE record"},{"source":"CVE 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record"}],"cvss":null,"severity":null,"kev":{"listed":false},"epss":{"probability":0.00168,"percentile":0.05749,"score_date":"2026-10-23"},"published_at":"2026-10-18T15:50:14.029Z","modified_at":"2026-10-21T12:57:25.411Z","provenance":[{"source":"CVE List","url":"https://www.cve.org/CVERecord?id=CVE-2026-98840","fetched_at":"2026-10-23T18:45:31.882637Z","source_modified_at":"2026-10-21T12:57:25.411Z"},{"source":"EPSS","url":"https://api.first.org/data/v1/epss?cve=CVE-2026-98840","fetched_at":"2026-10-23T18:42:43.628194Z","source_modified_at":"2026-10-23"}],"sources":["CVE List","EPSS"],"references":[{"source":"CVE List","url":"https://git.kernel.org/stable/c/c073d01f6f5367c3a4f07efd507274ed0d03acd0"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/1485a3dd97ab1af2605243cabe6b604546d46dd1"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/233a2e190b12884d186027d0b86d43a48799b69c"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/9dfcadc5e003fb250dd471db90144bd5366140e9"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/226bd5603371cd9f6642cbb9e9a677f445de3530"}],"locations":[],"motoko_assessment":{"status":"requires_architecture_review","automatic_remediation":false},"cve_state":"PUBLISHED","classification":{"method":"product-first software-layer rules","rules_version":"2.1","matched_on":"product","confidence":"heuristic","reviewed":false},"change_timestamp":"2026-10-21T12:57:25.411Z","content_hash":"121ec87a4901889a540c5273ef249155d7eaba986938f8946ee971330d76ed13"}}