{"api_version":"1","generated_at":"2026-10-21T16:51:54+00:00","cve":"CVE-2026-98840","urls":{"html":"https://cve.report/CVE-2026-98840","api":"https://cve.report/api/cve/CVE-2026-98840.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-98840","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-98840"},"summary":{"title":"vc_screen: reload vc pointer before if (ret) in vcs_write() to avoid UAF","description":"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().","state":"PUBLISHED","assigner":"Linux","published_at":"2026-10-18 16:17:38","updated_at":"2026-10-21 13:21:49"},"problem_types":[],"metrics":[],"references":[{"url":"https://git.kernel.org/stable/c/1485a3dd97ab1af2605243cabe6b604546d46dd1","name":"https://git.kernel.org/stable/c/1485a3dd97ab1af2605243cabe6b604546d46dd1","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/226bd5603371cd9f6642cbb9e9a677f445de3530","name":"https://git.kernel.org/stable/c/226bd5603371cd9f6642cbb9e9a677f445de3530","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/9dfcadc5e003fb250dd471db90144bd5366140e9","name":"https://git.kernel.org/stable/c/9dfcadc5e003fb250dd471db90144bd5366140e9","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/233a2e190b12884d186027d0b86d43a48799b69c","name":"https://git.kernel.org/stable/c/233a2e190b12884d186027d0b86d43a48799b69c","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/c073d01f6f5367c3a4f07efd507274ed0d03acd0","name":"https://git.kernel.org/stable/c/c073d01f6f5367c3a4f07efd507274ed0d03acd0","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-98840","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-98840","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 8232fca738011ca2ec865b46ec721d1796dc0580 c073d01f6f5367c3a4f07efd507274ed0d03acd0 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 73049768ad57145acd337102c5aa3c788e6642c8 1485a3dd97ab1af2605243cabe6b604546d46dd1 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 7cc3dd79777f6ae4625ec37e84dd18a26dc88bde 233a2e190b12884d186027d0b86d43a48799b69c git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected a287620312dc6dcb9a093417a0e589bf30fcf38a 9dfcadc5e003fb250dd471db90144bd5366140e9 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected a287620312dc6dcb9a093417a0e589bf30fcf38a 226bd5603371cd9f6642cbb9e9a677f445de3530 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 43a6281790273c1b0a9ab76609ff0245b968f1e6 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected b6bbb85cf45bf0b070e741997fe0af3a772c5ad5 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected ff4806202749a51938236214adc0281481a57366 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 74be188eb2dc1c99d63986167b9a67d415fe7326 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 09a43e81279b8da15526da09877134b8bcf618b0 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6.6.144 6.6.160 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6.12.95 6.12.113 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6.18.37 6.18.56 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 5.10.260 5.11 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 5.15.211 5.16 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6.1.177 6.2 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 7.0.14 7.1 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 7.1.2 7.2 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 7.2","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.2 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.6.160 6.6.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12.113 6.12.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.56 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.2.10 7.2.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.3 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":null,"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["drivers/tty/vt/vc_screen.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"c073d01f6f5367c3a4f07efd507274ed0d03acd0","status":"affected","version":"8232fca738011ca2ec865b46ec721d1796dc0580","versionType":"git"},{"lessThan":"1485a3dd97ab1af2605243cabe6b604546d46dd1","status":"affected","version":"73049768ad57145acd337102c5aa3c788e6642c8","versionType":"git"},{"lessThan":"233a2e190b12884d186027d0b86d43a48799b69c","status":"affected","version":"7cc3dd79777f6ae4625ec37e84dd18a26dc88bde","versionType":"git"},{"lessThan":"9dfcadc5e003fb250dd471db90144bd5366140e9","status":"affected","version":"a287620312dc6dcb9a093417a0e589bf30fcf38a","versionType":"git"},{"lessThan":"226bd5603371cd9f6642cbb9e9a677f445de3530","status":"affected","version":"a287620312dc6dcb9a093417a0e589bf30fcf38a","versionType":"git"},{"status":"affected","version":"43a6281790273c1b0a9ab76609ff0245b968f1e6","versionType":"git"},{"status":"affected","version":"b6bbb85cf45bf0b070e741997fe0af3a772c5ad5","versionType":"git"},{"status":"affected","version":"ff4806202749a51938236214adc0281481a57366","versionType":"git"},{"status":"affected","version":"74be188eb2dc1c99d63986167b9a67d415fe7326","versionType":"git"},{"status":"affected","version":"09a43e81279b8da15526da09877134b8bcf618b0","versionType":"git"},{"lessThan":"6.6.160","status":"affected","version":"6.6.144","versionType":"semver"},{"lessThan":"6.12.113","status":"affected","version":"6.12.95","versionType":"semver"},{"lessThan":"6.18.56","status":"affected","version":"6.18.37","versionType":"semver"},{"lessThan":"5.11","status":"affected","version":"5.10.260","versionType":"semver"},{"lessThan":"5.16","status":"affected","version":"5.15.211","versionType":"semver"},{"lessThan":"6.2","status":"affected","version":"6.1.177","versionType":"semver"},{"lessThan":"7.1","status":"affected","version":"7.0.14","versionType":"semver"},{"lessThan":"7.2","status":"affected","version":"7.1.2","versionType":"semver"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["drivers/tty/vt/vc_screen.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"7.2"},{"lessThan":"7.2","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"6.6.*","status":"unaffected","version":"6.6.160","versionType":"semver"},{"lessThanOrEqual":"6.12.*","status":"unaffected","version":"6.12.113","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.56","versionType":"semver"},{"lessThanOrEqual":"7.2.*","status":"unaffected","version":"7.2.10","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.3","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.6.160","versionStartIncluding":"6.6.144","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.12.113","versionStartIncluding":"6.12.95","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.56","versionStartIncluding":"6.18.37","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.2.10","versionStartIncluding":"7.2","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.3","versionStartIncluding":"7.2","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.10.260","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.15.211","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.1.177","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"7.0.14","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"7.1.2","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"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()."}],"providerMetadata":{"dateUpdated":"2026-10-21T12:57:25.411Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/c073d01f6f5367c3a4f07efd507274ed0d03acd0"},{"url":"https://git.kernel.org/stable/c/1485a3dd97ab1af2605243cabe6b604546d46dd1"},{"url":"https://git.kernel.org/stable/c/233a2e190b12884d186027d0b86d43a48799b69c"},{"url":"https://git.kernel.org/stable/c/9dfcadc5e003fb250dd471db90144bd5366140e9"},{"url":"https://git.kernel.org/stable/c/226bd5603371cd9f6642cbb9e9a677f445de3530"}],"title":"vc_screen: reload vc pointer before if (ret) in vcs_write() to avoid UAF","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-98840","datePublished":"2026-10-18T15:50:14.029Z","dateReserved":"2026-09-25T10:25:14.373Z","dateUpdated":"2026-10-21T12:57:25.411Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-10-18 16:17:38","lastModifiedDate":"2026-10-21 13:21:49","problem_types":[],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"98840","Ordinal":"1","Title":"vc_screen: reload vc pointer before if (ret) in vcs_write() to a","CVE":"CVE-2026-98840","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"98840","Ordinal":"1","NoteData":"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().","Type":"Description","Title":"vc_screen: reload vc pointer before if (ret) in vcs_write() to a"}]}}}