{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2023-52973", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2025-03-27T16:40:15.737Z", "datePublished": "2025-03-27T16:43:12.756Z", "dateUpdated": "2026-08-05T09:12:11.113Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T09:12:11.113Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nvc_screen: move load of struct vc_data pointer in vcs_read() to avoid UAF\n\nAfter a call to console_unlock() in vcs_read() the vc_data struct can be\nfreed by vc_deallocate(). Because of that, the struct vc_data pointer\nload must be done at the top of while loop in vcs_read() to avoid a UAF\nwhen vcs_size() is called.\n\nSyzkaller reported a UAF in vcs_size().\n\nBUG: KASAN: use-after-free in vcs_size (drivers/tty/vt/vc_screen.c:215)\nRead of size 4 at addr ffff8881137479a8 by task 4a005ed81e27e65/1537\n\nCPU: 0 PID: 1537 Comm: 4a005ed81e27e65 Not tainted 6.2.0-rc5 #1\nHardware name: Red Hat KVM, BIOS 1.15.0-2.module\nCall Trace:\n \n__asan_report_load4_noabort (mm/kasan/report_generic.c:350)\nvcs_size (drivers/tty/vt/vc_screen.c:215)\nvcs_read (drivers/tty/vt/vc_screen.c:415)\nvfs_read (fs/read_write.c:468 fs/read_write.c:450)\n...\n \n\nAllocated by task 1191:\n...\nkmalloc_trace (mm/slab_common.c:1069)\nvc_allocate (./include/linux/slab.h:580 ./include/linux/slab.h:720\n drivers/tty/vt/vt.c:1128 drivers/tty/vt/vt.c:1108)\ncon_install (drivers/tty/vt/vt.c:3383)\ntty_init_dev (drivers/tty/tty_io.c:1301 drivers/tty/tty_io.c:1413\n drivers/tty/tty_io.c:1390)\ntty_open (drivers/tty/tty_io.c:2080 drivers/tty/tty_io.c:2126)\nchrdev_open (fs/char_dev.c:415)\ndo_dentry_open (fs/open.c:883)\nvfs_open (fs/open.c:1014)\n...\n\nFreed by task 1548:\n...\nkfree (mm/slab_common.c:1021)\nvc_port_destruct (drivers/tty/vt/vt.c:1094)\ntty_port_destructor (drivers/tty/tty_port.c:296)\ntty_port_put (drivers/tty/tty_port.c:312)\nvt_disallocate_all (drivers/tty/vt/vt_ioctl.c:662 (discriminator 2))\nvt_ioctl (drivers/tty/vt/vt_ioctl.c:903)\ntty_ioctl (drivers/tty/tty_io.c:2776)\n...\n\nThe buggy address belongs to the object at ffff888113747800\n which belongs to the cache kmalloc-1k of size 1024\nThe buggy address is located 424 bytes inside of\n 1024-byte region [ffff888113747800, ffff888113747c00)\n\nThe buggy address belongs to the physical page:\npage:00000000b3fe6c7c refcount:1 mapcount:0 mapping:0000000000000000\n index:0x0 pfn:0x113740\nhead:00000000b3fe6c7c order:3 compound_mapcount:0 subpages_mapcount:0\n compound_pincount:0\nanon flags: 0x17ffffc0010200(slab|head|node=0|zone=2|lastcpupid=0x1fffff)\nraw: 0017ffffc0010200 ffff888100042dc0 0000000000000000 dead000000000001\nraw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000\npage dumped because: kasan: bad access detected\n\nMemory state around the buggy address:\n ffff888113747880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb\n ffff888113747900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb\n> ffff888113747980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb\n ^\n ffff888113747a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb\n ffff888113747a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb\n==================================================================\nDisabling lock debugging due to kernel taint" } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 7.8, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:L - The vulnerability is reached via open/read on /dev/vcs* character devices (vcs_read), which requires local system access through the VFS syscall path, not network or adjacent network access.\nAC:L - The attacker controls both sides of the race—one thread reading a large buffer from /dev/vcsN and another issuing VT_DISALLOCATE on a VT tty—so success does not depend on conditions outside attacker influence.\nPR:L - Exploitation needs only an unprivileged local account with access to a VT tty and /dev/vcs* (e.g., tty group or console login); VT_DISALLOCATE notably performs no perm/capability check, so real root is not required.\nUI:N - The attacker opens the devices and triggers the race themselves with no action required from another user.\nS:U - This is a standard in-kernel use-after-free enabling privilege escalation within the same kernel security authority, with no VM escape or cross-boundary impact.\nC:H - Use-after-free of the kmalloc-1k vc_data object allows heap spraying so subsequent vcs_size/vcs_read_buf accesses can disclose arbitrary kernel memory to userspace.\nI:H - Kernel UAF of a sprayed slab object enables classic heap exploitation primitives for arbitrary write and control-flow hijacking beyond a mere crash.\nA:H - The UAF reliably produces KASAN-detectable use-after-free faults and can cause kernel oops/panic when the freed vc_data is dereferenced." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/tty/vt/vc_screen.c" ], "versions": [ { "version": "ac751efa6a0d70f2c9daef5c7e3a92270f5c2dff", "lessThan": "af79ea9a2443016f64d8fd8d72020cc874f0e066", "status": "affected", "versionType": "git" }, { "version": "ac751efa6a0d70f2c9daef5c7e3a92270f5c2dff", "lessThan": "6332f52f44b9776568bf3c0b714ddfb0bb175e78", "status": "affected", "versionType": "git" }, { "version": "ac751efa6a0d70f2c9daef5c7e3a92270f5c2dff", "lessThan": "d0332cbf53dad06a22189cc341391237f4ea6d9f", "status": "affected", "versionType": "git" }, { "version": "ac751efa6a0d70f2c9daef5c7e3a92270f5c2dff", "lessThan": "55515d7d8743b71b80bfe68e89eb9d92630626ab", "status": "affected", "versionType": "git" }, { "version": "ac751efa6a0d70f2c9daef5c7e3a92270f5c2dff", "lessThan": "fc9e27f3ba083534b8bbf72ab0f5c810ffdc7d18", "status": "affected", "versionType": "git" }, { "version": "ac751efa6a0d70f2c9daef5c7e3a92270f5c2dff", "lessThan": "8506f16aae9daf354e3732bcfd447e2a97f023df", "status": "affected", "versionType": "git" }, { "version": "ac751efa6a0d70f2c9daef5c7e3a92270f5c2dff", "lessThan": "226fae124b2dac217ea5436060d623ff3385bc34", "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/tty/vt/vc_screen.c" ], "versions": [ { "version": "2.6.38", "status": "affected" }, { "version": "0", "lessThan": "2.6.38", "status": "unaffected", "versionType": "semver" }, { "version": "4.14.329", "lessThanOrEqual": "4.14.*", "status": "unaffected", "versionType": "semver" }, { "version": "4.19.273", "lessThanOrEqual": "4.19.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.4.232", "lessThanOrEqual": "5.4.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.168", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.93", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.11", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.2", "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": "2.6.38", "versionEndExcluding": "4.14.329" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.38", "versionEndExcluding": "4.19.273" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.38", "versionEndExcluding": "5.4.232" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.38", "versionEndExcluding": "5.10.168" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.38", "versionEndExcluding": "5.15.93" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.38", "versionEndExcluding": "6.1.11" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.38", "versionEndExcluding": "6.2" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/af79ea9a2443016f64d8fd8d72020cc874f0e066" }, { "url": "https://git.kernel.org/stable/c/6332f52f44b9776568bf3c0b714ddfb0bb175e78" }, { "url": "https://git.kernel.org/stable/c/d0332cbf53dad06a22189cc341391237f4ea6d9f" }, { "url": "https://git.kernel.org/stable/c/55515d7d8743b71b80bfe68e89eb9d92630626ab" }, { "url": "https://git.kernel.org/stable/c/fc9e27f3ba083534b8bbf72ab0f5c810ffdc7d18" }, { "url": "https://git.kernel.org/stable/c/8506f16aae9daf354e3732bcfd447e2a97f023df" }, { "url": "https://git.kernel.org/stable/c/226fae124b2dac217ea5436060d623ff3385bc34" } ], "title": "vc_screen: move load of struct vc_data pointer in vcs_read() to avoid UAF", "x_generator": { "engine": "bippy-1.2.0" } }, "adp": [ { "metrics": [ { "cvssV3_1": { "scope": "UNCHANGED", "version": "3.1", "baseScore": 7.8, "attackVector": "LOCAL", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "integrityImpact": "HIGH", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "LOW", "confidentialityImpact": "HIGH" } }, { "other": { "type": "ssvc", "content": { "id": "CVE-2023-52973", "role": "CISA Coordinator", "options": [ { "Exploitation": "none" }, { "Automatable": "no" }, { "Technical Impact": "total" } ], "version": "2.0.3", "timestamp": "2025-03-27T16:59:54.662104Z" } } } ], "problemTypes": [ { "descriptions": [ { "lang": "en", "type": "CWE", "cweId": "CWE-416", "description": "CWE-416 Use After Free" } ] } ], "title": "CISA ADP Vulnrichment", "providerMetadata": { "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2025-03-27T17:08:22.708Z" } } ] } }