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NVD / CVE Program· CNA Linux

CVE-2023-52973: vc_screen: move load of struct vc_data pointer in vcs_read() to avoid UAF

Noroxi assessment

Priority: Monitor (action score 31/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.28% (FIRST EPSS).
  • Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: Linux Linux 226fae124b2dac217ea5436060d623ff3385bc34, 55515d7d8743b71b80bfe68e89eb9d92630626ab, 6332f52f44b9776568bf3c0b714ddfb0bb175e78.

Low priority for now. Upgrade to Linux Linux 226fae124b2dac217ea5436060d623ff3385bc34, 55515d7d8743b71b80bfe68e89eb9d92630626ab, 6332f52f44b9776568bf3c0b714ddfb0bb175e78 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

In the Linux kernel, the following vulnerability has been resolved: vc_screen: move load of struct vc_data pointer in vcs_read() to avoid UAF After a call to console_unlock() in vcs_read() the vc_data struct can be freed by vc_deallocate(). Because of that, the struct vc_data pointer load must be done at the top of while loop in vcs_read() to avoid a UAF when vcs_size() is called. Syzkaller reported a UAF in vcs_size(). BUG: KASAN: use-after-free in vcs_size (drivers/tty/vt/vc_screen.c:215) Read of size 4 at addr ffff8881137479a8 by task 4a005ed81e27e65/1537 CPU: 0 PID: 1537 Comm: 4a005ed81e27e65 Not tainted 6.2.0-rc5 #1 Hardware name: Red Hat KVM, BIOS 1.15.0-2.module Call Trace: <TASK> __asan_report_load4_noabort (mm/kasan/report_generic.c:350) vcs_size (drivers/tty/vt/vc_screen.c:215) vcs_read (drivers/tty/vt/vc_screen.c:415) vfs_read (fs/read_write.c:468 fs/read_write.c:450) ... </TASK> Allocated by task 1191: ... kmalloc_trace (mm/slab_common.c:1069) vc_allocate (./include/linux/slab.h:580 ./include/linux/slab.h:720 drivers/tty/vt/vt.c:1128 drivers/tty/vt/vt.c:1108) con_install (drivers/tty/vt/vt.c:3383) tty_init_dev (drivers/tty/tty_io.c:1301 drivers/tty/tty_io.c:1413 drivers/tty/tty_io.c:1390) tty_open (drivers/tty/tty_io.c:2080 drivers/tty/tty_io.c:2126) chrdev_open (fs/char_dev.c:415) do_dentry_open (fs/open.c:883) vfs_open (fs/open.c:1014) ... Freed by task 1548: ... kfree (mm/slab_common.c:1021) vc_port_destruct (drivers/tty/vt/vt.c:1094) tty_port_destructor (drivers/tty/tty_port.c:296) tty_port_put (drivers/tty/tty_port.c:312) vt_disallocate_all (drivers/tty/vt/vt_ioctl.c:662 (discriminator 2)) vt_ioctl (drivers/tty/vt/vt_ioctl.c:903) tty_ioctl (drivers/tty/tty_io.c:2776) ... The buggy address belongs to the object at ffff888113747800 which belongs to the cache kmalloc-1k of size 1024 The buggy address is located 424 bytes inside of 1024-byte region [ffff888113747800, ffff888113747c00) The buggy address belongs to the physical page: page:00000000b3fe6c7c refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x113740 head:00000000b3fe6c7c order:3 compound_mapcount:0 subpages_mapcount:0 compound_pincount:0 anon flags: 0x17ffffc0010200(slab|head|node=0|zone=2|lastcpupid=0x1fffff) raw: 0017ffffc0010200 ffff888100042dc0 0000000000000000 dead000000000001 raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff888113747880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888113747900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ffff888113747980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888113747a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888113747a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== Disabling lock debugging due to kernel taint

HighCVSS 7.8 · v3.1—No exploit Fix available
Published
Mar 27, 2025
Updated
Aug 5, 2026
EPSS
0.2% · 21th percentile

Report tools

JSON

Action score

31

Monitor

Low priority for now.

CVSS
31 / 40 · 7.8 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.2%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · Linux
7.8
NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

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  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
linuxlinux kernel

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • linux linux kernel2.6.38 and later · before 4.14.329
  • linux linux kernel4.15 and later · before 4.19.273
  • linux linux kernel4.20 and later · before 5.4.232
  • linux linux kernel5.5 and later · before 5.10.168
  • linux linux kernel5.11 and later · before 5.15.93
  • linux linux kernel5.16 and later · before 6.1.11
  • linux linux kernel6.2

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

  • Linux Linux

    • 2.6.38affected
    • ac751efa6a0d70f2c9daef5c7e3a92270f5c2dff and later · before af79ea9a2443016f64d8fd8d72020cc874f0e066affected · git
    • ac751efa6a0d70f2c9daef5c7e3a92270f5c2dff and later · before 6332f52f44b9776568bf3c0b714ddfb0bb175e78affected · git
    • ac751efa6a0d70f2c9daef5c7e3a92270f5c2dff and later · before d0332cbf53dad06a22189cc341391237f4ea6d9faffected · git
    • ac751efa6a0d70f2c9daef5c7e3a92270f5c2dff and later · before 55515d7d8743b71b80bfe68e89eb9d92630626abaffected · git
    • ac751efa6a0d70f2c9daef5c7e3a92270f5c2dff and later · before fc9e27f3ba083534b8bbf72ab0f5c810ffdc7d18affected · git
    • ac751efa6a0d70f2c9daef5c7e3a92270f5c2dff and later · before 8506f16aae9daf354e3732bcfd447e2a97f023dfaffected · git
    • ac751efa6a0d70f2c9daef5c7e3a92270f5c2dff and later · before 226fae124b2dac217ea5436060d623ff3385bc34affected · git
    • before 2.6.38not affected · semver
    • 4.14.329 and later · up to and including 4.14.*not affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.11-16.1.11-1
Red Hat:rhel_eus:9.2::nfvkernel-rtbefore 0:5.14.0-284.48.1.rt14.333.el9_20:5.14.0-284.48.1.rt14.333.el9_2
Red Hat:rhel_eus:9.2::nfvkernel-rt-corebefore 0:5.14.0-284.48.1.rt14.333.el9_20:5.14.0-284.48.1.rt14.333.el9_2
Red Hat:rhel_eus:9.2::nfvkernel-rt-debugbefore 0:5.14.0-284.48.1.rt14.333.el9_20:5.14.0-284.48.1.rt14.333.el9_2
Red Hat:rhel_eus:9.2::nfvkernel-rt-debug-corebefore 0:5.14.0-284.48.1.rt14.333.el9_20:5.14.0-284.48.1.rt14.333.el9_2
Red Hat:rhel_eus:9.2::nfvkernel-rt-debug-debuginfobefore 0:5.14.0-284.48.1.rt14.333.el9_20:5.14.0-284.48.1.rt14.333.el9_2
Red Hat:rhel_eus:9.2::nfvkernel-rt-debug-develbefore 0:5.14.0-284.48.1.rt14.333.el9_20:5.14.0-284.48.1.rt14.333.el9_2
Red Hat:rhel_eus:9.2::nfvkernel-rt-debug-kvmbefore 0:5.14.0-284.48.1.rt14.333.el9_20:5.14.0-284.48.1.rt14.333.el9_2
Red Hat:rhel_eus:9.2::nfvkernel-rt-debug-modulesbefore 0:5.14.0-284.48.1.rt14.333.el9_20:5.14.0-284.48.1.rt14.333.el9_2
Red Hat:rhel_eus:9.2::nfvkernel-rt-debug-modules-corebefore 0:5.14.0-284.48.1.rt14.333.el9_20:5.14.0-284.48.1.rt14.333.el9_2
Red Hat:rhel_eus:9.2::nfvkernel-rt-debug-modules-extrabefore 0:5.14.0-284.48.1.rt14.333.el9_20:5.14.0-284.48.1.rt14.333.el9_2
Red Hat:rhel_eus:9.2::nfvkernel-rt-debuginfobefore 0:5.14.0-284.48.1.rt14.333.el9_20:5.14.0-284.48.1.rt14.333.el9_2
Red Hat:rhel_eus:9.2::nfvkernel-rt-debuginfo-common-x86_64before 0:5.14.0-284.48.1.rt14.333.el9_20:5.14.0-284.48.1.rt14.333.el9_2
Red Hat:rhel_eus:9.2::nfvkernel-rt-develbefore 0:5.14.0-284.48.1.rt14.333.el9_20:5.14.0-284.48.1.rt14.333.el9_2
Red Hat:rhel_eus:9.2::nfvkernel-rt-kvmbefore 0:5.14.0-284.48.1.rt14.333.el9_20:5.14.0-284.48.1.rt14.333.el9_2
Red Hat:rhel_eus:9.2::nfvkernel-rt-modulesbefore 0:5.14.0-284.48.1.rt14.333.el9_20:5.14.0-284.48.1.rt14.333.el9_2
Red Hat:rhel_eus:9.2::nfvkernel-rt-modules-corebefore 0:5.14.0-284.48.1.rt14.333.el9_20:5.14.0-284.48.1.rt14.333.el9_2
Red Hat:rhel_eus:9.2::nfvkernel-rt-modules-extrabefore 0:5.14.0-284.48.1.rt14.333.el9_20:5.14.0-284.48.1.rt14.333.el9_2
SUSE:Linux Enterprise Server 11 SP4 LTSS EXTREME COREkernel-defaultbefore 3.0.101-108.183.13.0.101-108.183.1
SUSE:Linux Enterprise Server 11 SP4 LTSS EXTREME COREkernel-ec2before 3.0.101-108.183.13.0.101-108.183.1
SUSE:Linux Enterprise Server 11 SP4 LTSS EXTREME COREkernel-sourcebefore 3.0.101-108.183.13.0.101-108.183.1
SUSE:Linux Enterprise Server 11 SP4 LTSS EXTREME COREkernel-symsbefore 3.0.101-108.183.13.0.101-108.183.1
SUSE:Linux Enterprise Server 11 SP4 LTSS EXTREME COREkernel-tracebefore 3.0.101-108.183.13.0.101-108.183.1
SUSE:Linux Enterprise Server 11 SP4 LTSS EXTREME COREkernel-xenbefore 3.0.101-108.183.13.0.101-108.183.1

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-31431crypto: algif_aead - Revert to operating out-of-placeKEV
    90Now
  • CVE-2022-0847A flaw was found in the way the "flags" member of the new pipe buffer structure was lacking proper initialization in copy_page_to_iter_pipe KEV
    89Now
  • CVE-2021-22555Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACEKEV
    85Now

Published before and after this one in the same product

  • ← EarlierCVE-2023-52940Mar 27, 2025 · mm: multi-gen LRU: fix crash during cgroup migration
    22Monitor
  • ← EarlierCVE-2023-52941Mar 27, 2025 · can: isotp: split tx timer into transmission and timeout
    22Monitor
  • Later →CVE-2023-52974Mar 27, 2025 · scsi: iscsi_tcp: Fix UAF during login when accessing the shost ipaddress
    31Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux226fae124b2dac217ea5436060d623ff3385bc34Vendor (CNA)
Linux Linux55515d7d8743b71b80bfe68e89eb9d92630626abVendor (CNA)
Linux Linux6332f52f44b9776568bf3c0b714ddfb0bb175e78Vendor (CNA)
Linux Linux8506f16aae9daf354e3732bcfd447e2a97f023dfVendor (CNA)
Linux Linuxaf79ea9a2443016f64d8fd8d72020cc874f0e066Vendor (CNA)
Linux Linuxd0332cbf53dad06a22189cc341391237f4ea6d9fVendor (CNA)
Linux Linuxfc9e27f3ba083534b8bbf72ab0f5c810ffdc7d18Vendor (CNA)
debian:linux6.1.11-1 · Debian:12Package registry (OSV)
red hat:kernel-rt0:5.14.0-284.48.1.rt14.333.el9_2 · Red Hat:rhel_eus:9.2::nfvPackage registry (OSV)
red hat:kernel-rt-core0:5.14.0-284.48.1.rt14.333.el9_2 · Red Hat:rhel_eus:9.2::nfvPackage registry (OSV)
red hat:kernel-rt-debug0:5.14.0-284.48.1.rt14.333.el9_2 · Red Hat:rhel_eus:9.2::nfvPackage registry (OSV)
red hat:kernel-rt-debug-core0:5.14.0-284.48.1.rt14.333.el9_2 · Red Hat:rhel_eus:9.2::nfvPackage registry (OSV)
red hat:kernel-rt-debug-debuginfo0:5.14.0-284.48.1.rt14.333.el9_2 · Red Hat:rhel_eus:9.2::nfvPackage registry (OSV)
red hat:kernel-rt-debug-devel0:5.14.0-284.48.1.rt14.333.el9_2 · Red Hat:rhel_eus:9.2::nfvPackage registry (OSV)
red hat:kernel-rt-debug-kvm0:5.14.0-284.48.1.rt14.333.el9_2 · Red Hat:rhel_eus:9.2::nfvPackage registry (OSV)
red hat:kernel-rt-debug-modules0:5.14.0-284.48.1.rt14.333.el9_2 · Red Hat:rhel_eus:9.2::nfvPackage registry (OSV)
red hat:kernel-rt-debug-modules-core0:5.14.0-284.48.1.rt14.333.el9_2 · Red Hat:rhel_eus:9.2::nfvPackage registry (OSV)
red hat:kernel-rt-debug-modules-extra0:5.14.0-284.48.1.rt14.333.el9_2 · Red Hat:rhel_eus:9.2::nfvPackage registry (OSV)
red hat:kernel-rt-debuginfo0:5.14.0-284.48.1.rt14.333.el9_2 · Red Hat:rhel_eus:9.2::nfvPackage registry (OSV)
red hat:kernel-rt-debuginfo-common-x86_640:5.14.0-284.48.1.rt14.333.el9_2 · Red Hat:rhel_eus:9.2::nfvPackage registry (OSV)
suse:kernel-default3.0.101-108.183.1 · SUSE:Linux Enterprise Server 11 SP4 LTSS EXTREME COREPackage registry (OSV)
suse:kernel-ec23.0.101-108.183.1 · SUSE:Linux Enterprise Server 11 SP4 LTSS EXTREME COREPackage registry (OSV)
suse:kernel-source3.0.101-108.183.1 · SUSE:Linux Enterprise Server 11 SP4 LTSS EXTREME COREPackage registry (OSV)
suse:kernel-syms3.0.101-108.183.1 · SUSE:Linux Enterprise Server 11 SP4 LTSS EXTREME COREPackage registry (OSV)
suse:kernel-trace3.0.101-108.183.1 · SUSE:Linux Enterprise Server 11 SP4 LTSS EXTREME COREPackage registry (OSV)
suse:kernel-xen3.0.101-108.183.1 · SUSE:Linux Enterprise Server 11 SP4 LTSS EXTREME COREPackage registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Someone with local access to the system can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
high · data can be read
Integrity
high · data or configuration can be modified
Availability
high · the service can be disrupted
Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

CWE-416 · Use After Free

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

nvd-secondary

Root cause

After a memory region is freed, another reference pointing to it is still used. By then, the same region may have been allocated for different data.

The bug in code

The whole CWE-416 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

c
free(dev->buf);/* ... another thread is still running ... */process(dev->buf);

Fixed

c
lock(&dev->lock);free(dev->buf);dev->buf = NULL;unlock(&dev->lock);

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (6 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records