Skip to content
Noroxi
NVD / CVE Program· CNA Linux

CVE-2023-52463: efivarfs: force RO when remounting if SetVariable is not supported

Noroxi assessment

Priority: Monitor (action score 22/100)

  • 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: 0.24% (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 0049fe7e4a85849bdd778cdb72e51a791ff3d737, 0e8d2444168dd519fea501599d150e62718ed2fe, 2aa141f8bc580f8f9811dfe4e0e6009812b73826.

Low priority for now. Upgrade to Linux Linux 0049fe7e4a85849bdd778cdb72e51a791ff3d737, 0e8d2444168dd519fea501599d150e62718ed2fe, 2aa141f8bc580f8f9811dfe4e0e6009812b73826 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: efivarfs: force RO when remounting if SetVariable is not supported If SetVariable at runtime is not supported by the firmware we never assign a callback for that function. At the same time mount the efivarfs as RO so no one can call that. However, we never check the permission flags when someone remounts the filesystem as RW. As a result this leads to a crash looking like this: $ mount -o remount,rw /sys/firmware/efi/efivars $ efi-updatevar -f PK.auth PK [ 303.279166] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000 [ 303.280482] Mem abort info: [ 303.280854] ESR = 0x0000000086000004 [ 303.281338] EC = 0x21: IABT (current EL), IL = 32 bits [ 303.282016] SET = 0, FnV = 0 [ 303.282414] EA = 0, S1PTW = 0 [ 303.282821] FSC = 0x04: level 0 translation fault [ 303.283771] user pgtable: 4k pages, 48-bit VAs, pgdp=000000004258c000 [ 303.284913] [0000000000000000] pgd=0000000000000000, p4d=0000000000000000 [ 303.286076] Internal error: Oops: 0000000086000004 [#1] PREEMPT SMP [ 303.286936] Modules linked in: qrtr tpm_tis tpm_tis_core crct10dif_ce arm_smccc_trng rng_core drm fuse ip_tables x_tables ipv6 [ 303.288586] CPU: 1 PID: 755 Comm: efi-updatevar Not tainted 6.3.0-rc1-00108-gc7d0c4695c68 #1 [ 303.289748] Hardware name: Unknown Unknown Product/Unknown Product, BIOS 2023.04-00627-g88336918701d 04/01/2023 [ 303.291150] pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) [ 303.292123] pc : 0x0 [ 303.292443] lr : efivar_set_variable_locked+0x74/0xec [ 303.293156] sp : ffff800008673c10 [ 303.293619] x29: ffff800008673c10 x28: ffff0000037e8000 x27: 0000000000000000 [ 303.294592] x26: 0000000000000800 x25: ffff000002467400 x24: 0000000000000027 [ 303.295572] x23: ffffd49ea9832000 x22: ffff0000020c9800 x21: ffff000002467000 [ 303.296566] x20: 0000000000000001 x19: 00000000000007fc x18: 0000000000000000 [ 303.297531] x17: 0000000000000000 x16: 0000000000000000 x15: 0000aaaac807ab54 [ 303.298495] x14: ed37489f673633c0 x13: 71c45c606de13f80 x12: 47464259e219acf4 [ 303.299453] x11: ffff000002af7b01 x10: 0000000000000003 x9 : 0000000000000002 [ 303.300431] x8 : 0000000000000010 x7 : ffffd49ea8973230 x6 : 0000000000a85201 [ 303.301412] x5 : 0000000000000000 x4 : ffff0000020c9800 x3 : 00000000000007fc [ 303.302370] x2 : 0000000000000027 x1 : ffff000002467400 x0 : ffff000002467000 [ 303.303341] Call trace: [ 303.303679] 0x0 [ 303.303938] efivar_entry_set_get_size+0x98/0x16c [ 303.304585] efivarfs_file_write+0xd0/0x1a4 [ 303.305148] vfs_write+0xc4/0x2e4 [ 303.305601] ksys_write+0x70/0x104 [ 303.306073] __arm64_sys_write+0x1c/0x28 [ 303.306622] invoke_syscall+0x48/0x114 [ 303.307156] el0_svc_common.constprop.0+0x44/0xec [ 303.307803] do_el0_svc+0x38/0x98 [ 303.308268] el0_svc+0x2c/0x84 [ 303.308702] el0t_64_sync_handler+0xf4/0x120 [ 303.309293] el0t_64_sync+0x190/0x194 [ 303.309794] Code: ???????? ???????? ???????? ???????? (????????) [ 303.310612] ---[ end trace 0000000000000000 ]--- Fix this by adding a .reconfigure() function to the fs operations which we can use to check the requested flags and deny anything that's not RO if the firmware doesn't implement SetVariable at runtime.

MediumCVSS 5.5 · v3.1—No exploit Fix available
Published
Feb 23, 2024
Updated
Jun 17, 2026
EPSS
0.2% · 15th percentile

Report tools

JSON

Action score

22

Monitor

Low priority for now.

CVSS
22 / 40 · 5.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.2%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

Get told when this record changes

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

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2023-52463

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

One daily email digest (06:00 UTC); connect a webhook for KEV listings and weaponized exploits instantly.

Your free account also gets you

Running WordPress? Scan your site free with WP Lens

  • Stack alerts: add the products and versions you run, get the new CVEs that affect them
  • Uptime monitoring: 1 site, instant email when it goes down
  • Add your domain: subdomains and takeover risk scanned every week (1 domain)
  • 10 scans an hour on the security tools (3 a day without an account), an API key and MCP
  • All your scans in one panel: findings, what changed in the last scan, a report per domain or per client (PDF, share link)
All free tools

Sign up with email · Have an account? Sign in

Free account, no card. Unfollow any time.

Don't want an account? Get "Exploited this week" by email every MondayDon't want an account? RSS feed for linux records

Running WordPress? Scan your site free with WP Lens

Is your version affected? Check it

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.

We use this product, ask for help

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 kernel5.8.0 and later · before 5.10.209
  • linux linux kernel5.11.0 and later · before 5.15.148
  • linux linux kernel5.16.0 and later · before 6.1.75
  • linux linux kernel6.2.0 and later · before 6.6.14
  • linux linux kernel6.7.0 and later · before 6.7.2

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

    • 552952e51fad35670459674bcb8a03bd96fe4646, 5.8affected
    • f88814cc2578c121e6edef686365036db72af0ed and later · before 94c742324ed7e42c5bd6a9ed22e4ec6d764db4d8affected · git
    • f88814cc2578c121e6edef686365036db72af0ed and later · before 2aa141f8bc580f8f9811dfe4e0e6009812b73826affected · git
    • f88814cc2578c121e6edef686365036db72af0ed and later · before d4a9aa7db574a0da64307729cc031fb68597aa8baffected · git
    • f88814cc2578c121e6edef686365036db72af0ed and later · before 0049fe7e4a85849bdd778cdb72e51a791ff3d737affected · git
    • f88814cc2578c121e6edef686365036db72af0ed and later · before d4a714873db0866cc471521114eeac4a5072d548affected · git
    • f88814cc2578c121e6edef686365036db72af0ed and later · before 0e8d2444168dd519fea501599d150e62718ed2feaffected · git
    • 5.7.11 and later · before 5.8affected · semver
    • before 5.8not affected · semver
    • 5.10.209 and later · up to and including 5.10.*not affected · semver

Package-level exposure

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

EcosystemPackageAffected rangeFix
AlmaLinux:8bpftoolbefore 4.18.0-553.16.1.el8_104.18.0-553.16.1.el8_10
AlmaLinux:8kernelbefore 4.18.0-553.16.1.el8_104.18.0-553.16.1.el8_10
AlmaLinux:8kernel-abi-stablelistsbefore 4.18.0-553.16.1.el8_104.18.0-553.16.1.el8_10
AlmaLinux:8kernel-corebefore 4.18.0-553.16.1.el8_104.18.0-553.16.1.el8_10
AlmaLinux:8kernel-cross-headersbefore 4.18.0-553.16.1.el8_104.18.0-553.16.1.el8_10
AlmaLinux:8kernel-debugbefore 4.18.0-553.16.1.el8_104.18.0-553.16.1.el8_10
AlmaLinux:8kernel-debug-corebefore 4.18.0-553.16.1.el8_104.18.0-553.16.1.el8_10
AlmaLinux:8kernel-debug-develbefore 4.18.0-553.16.1.el8_104.18.0-553.16.1.el8_10
AlmaLinux:8kernel-debug-modulesbefore 4.18.0-553.16.1.el8_104.18.0-553.16.1.el8_10
AlmaLinux:8kernel-debug-modules-extrabefore 4.18.0-553.16.1.el8_104.18.0-553.16.1.el8_10
AlmaLinux:8kernel-develbefore 4.18.0-553.16.1.el8_104.18.0-553.16.1.el8_10
AlmaLinux:8kernel-docbefore 4.18.0-553.16.1.el8_104.18.0-553.16.1.el8_10
AlmaLinux:8kernel-headersbefore 4.18.0-553.16.1.el8_104.18.0-553.16.1.el8_10
AlmaLinux:8kernel-modulesbefore 4.18.0-553.16.1.el8_104.18.0-553.16.1.el8_10
AlmaLinux:8kernel-modules-extrabefore 4.18.0-553.16.1.el8_104.18.0-553.16.1.el8_10
AlmaLinux:8kernel-rtbefore 4.18.0-553.16.1.rt7.357.el8_104.18.0-553.16.1.rt7.357.el8_10
AlmaLinux:8kernel-rt-corebefore 4.18.0-553.16.1.rt7.357.el8_104.18.0-553.16.1.rt7.357.el8_10
AlmaLinux:8kernel-rt-debugbefore 4.18.0-553.16.1.rt7.357.el8_104.18.0-553.16.1.rt7.357.el8_10
AlmaLinux:8kernel-rt-debug-corebefore 4.18.0-553.16.1.rt7.357.el8_104.18.0-553.16.1.rt7.357.el8_10
AlmaLinux:8kernel-rt-debug-develbefore 4.18.0-553.16.1.rt7.357.el8_104.18.0-553.16.1.rt7.357.el8_10
AlmaLinux:8kernel-rt-debug-kvmbefore 4.18.0-553.16.1.rt7.357.el8_104.18.0-553.16.1.rt7.357.el8_10
AlmaLinux:8kernel-rt-debug-modulesbefore 4.18.0-553.16.1.rt7.357.el8_104.18.0-553.16.1.rt7.357.el8_10
AlmaLinux:8kernel-rt-debug-modules-extrabefore 4.18.0-553.16.1.rt7.357.el8_104.18.0-553.16.1.rt7.357.el8_10
AlmaLinux:8kernel-rt-develbefore 4.18.0-553.16.1.rt7.357.el8_104.18.0-553.16.1.rt7.357.el8_10

+96

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-2023-52461Feb 23, 2024 · drm/sched: Fix bounds limiting when given a malformed entity
    31Monitor
  • ← EarlierCVE-2023-52462Feb 23, 2024 · bpf: fix check for attempt to corrupt spilled pointer
    22Monitor
  • Later →CVE-2024-26595Feb 23, 2024 · mlxsw: spectrum_acl_tcam: Fix NULL pointer dereference in error path
    22Monitor

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 Linux0049fe7e4a85849bdd778cdb72e51a791ff3d737Vendor (CNA)
Linux Linux0e8d2444168dd519fea501599d150e62718ed2feVendor (CNA)
Linux Linux2aa141f8bc580f8f9811dfe4e0e6009812b73826Vendor (CNA)
Linux Linux5.8Vendor (CNA)
Linux Linux94c742324ed7e42c5bd6a9ed22e4ec6d764db4d8Vendor (CNA)
Linux Linuxd4a714873db0866cc471521114eeac4a5072d548Vendor (CNA)
Linux Linuxd4a9aa7db574a0da64307729cc031fb68597aa8bVendor (CNA)
almalinux:bpftool4.18.0-553.16.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel4.18.0-553.16.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-abi-stablelists4.18.0-553.16.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-core4.18.0-553.16.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-cross-headers4.18.0-553.16.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-debug4.18.0-553.16.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-debug-core4.18.0-553.16.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-debug-devel4.18.0-553.16.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-debug-modules4.18.0-553.16.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-debug-modules-extra4.18.0-553.16.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-devel4.18.0-553.16.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-doc4.18.0-553.16.1.el8_10 · AlmaLinux:8Package registry (OSV)
debian:linux6.1.76-1 · Debian:12Package registry (OSV)
debian:linux-5.105.10.209-2~deb10u1 · Debian:10Package registry (OSV)
opensuse:dtb-aarch645.14.21-150500.55.52.1 · openSUSE:Leap 15.5Package registry (OSV)
opensuse:kernel-64kb5.14.21-150500.55.52.1 · openSUSE:Leap 15.5Package registry (OSV)
opensuse:kernel-debug5.14.21-150500.55.52.1 · openSUSE:Leap 15.5Package registry (OSV)
opensuse:kernel-default5.14.21-150500.55.52.1 · openSUSE:Leap 15.5Package registry (OSV)
opensuse:kernel-default-base5.14.21-150500.55.52.1.150500.6.23.1 · openSUSE:Leap 15.5Package registry (OSV)
opensuse:kernel-docs5.14.21-150500.55.52.1 · openSUSE:Leap 15.5Package registry (OSV)
opensuse:kernel-kvmsmall5.14.21-150500.55.52.1 · openSUSE:Leap 15.5Package registry (OSV)
opensuse:kernel-obs-build5.14.21-150500.55.52.1 · openSUSE:Leap 15.5Package registry (OSV)
opensuse:kernel-obs-qa5.14.21-150500.55.52.1 · openSUSE:Leap 15.5Package registry (OSV)

+29

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

Weakness class (CWE)

CWE-476 · NULL Pointer Dereference

CVSS vector

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

nvd-primary

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