CVE-2023-54203

UNRATEDCVSS · not yet scored
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EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • No CVSS published and no exploitation signals yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS v2: —Exploit: None knownExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

In the Linux kernel, the following vulnerability has been resolved:

ksmbd: fix slab-out-of-bounds in init_smb2_rsp_hdr

When smb1 mount fails, KASAN detect slab-out-of-bounds in init_smb2_rsp_hdr like the following one. For smb1 negotiate(56bytes) , init_smb2_rsp_hdr() for smb2 is called. The issue occurs while handling smb1 negotiate as smb2 server operations. Add smb server operations for smb1 (get_cmd_val, init_rsp_hdr, allocate_rsp_buf, check_user_session) to handle smb1 negotiate so that smb2 server operation does not handle it.

[ 411.400423] CIFS: VFS: Use of the less secure dialect vers=1.0 is not recommended unless required for access to very old servers [ 411.400452] CIFS: Attempting to mount \\192.168.45.139\homes [ 411.479312] ksmbd: init_smb2_rsp_hdr : 492 [ 411.479323] ================================================================== [ 411.479327] BUG: KASAN: slab-out-of-bounds in init_smb2_rsp_hdr+0x1e2/0x1f4 [ksmbd] [ 411.479369] Read of size 16 at addr ffff888488ed0734 by task kworker/14:1/199

[ 411.479379] CPU: 14 PID: 199 Comm: kworker/14:1 Tainted: G OE 6.1.21 #3 [ 411.479386] Hardware name: ASUSTeK COMPUTER INC. Z10PA-D8 Series/Z10PA-D8 Series, BIOS 3801 08/23/2019 [ 411.479390] Workqueue: ksmbd-io handle_ksmbd_work [ksmbd] [ 411.479425] Call Trace: [ 411.479428] [ 411.479432] dump_stack_lvl+0x49/0x63 [ 411.479444] print_report+0x171/0x4a8 [ 411.479452] ? kasan_complete_mode_report_info+0x3c/0x200 [ 411.479463] ? init_smb2_rsp_hdr+0x1e2/0x1f4 [ksmbd] [ 411.479497] kasan_report+0xb4/0x130 [ 411.479503] ? init_smb2_rsp_hdr+0x1e2/0x1f4 [ksmbd] [ 411.479537] kasan_check_range+0x149/0x1e0 [ 411.479543] memcpy+0x24/0x70 [ 411.479550] init_smb2_rsp_hdr+0x1e2/0x1f4 [ksmbd] [ 411.479585] handle_ksmbd_work+0x109/0x760 [ksmbd] [ 411.479616] ? _raw_spin_unlock_irqrestore+0x50/0x50 [ 411.479624] ? smb3_encrypt_resp+0x340/0x340 [ksmbd] [ 411.479656] process_one_work+0x49c/0x790 [ 411.479667] worker_thread+0x2b1/0x6e0 [ 411.479674] ? process_one_work+0x790/0x790 [ 411.479680] kthread+0x177/0x1b0 [ 411.479686] ? kthread_complete_and_exit+0x30/0x30 [ 411.479692] ret_from_fork+0x22/0x30 [ 411.479702]

CVSS v3
—
EchelonGraph score
Not yet assessedNo source has published severity data for this CVE yet — no CVSS score from NVD or a CNA, no GitHub advisory, and it is not in CISA KEV. This is not a rating of zero; we cannot assess it yet.
EG Score
—
EG Risk
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EPSS PROB
0%
EPSS %ILE
7%
KEV
Not listed

Published

December 30, 2025

Last Modified

April 15, 2026

References (4)

Patch Availability(1)

Vendor / EcosystemFixed in / PatchReleasedSource
linuxKernel @ 5.15.145—osv

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Data Freshness Timeline

(refreshed 7× in last 7d / 42× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 126 total refreshes for this CVE.

  1. 2026-08-01 04:14 UTCEPSS rescore
  2. 2026-07-30 16:26 UTCEPSS rescore
  3. 2026-07-30 01:29 UTCEPSS rescore
  4. 2026-07-28 15:34 UTCEPSS rescore
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  6. 2026-07-27 03:09 UTCOSV refresh
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  10. 2026-07-23 02:30 UTCEG score recompute
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  1. 2026-07-13 22:28 UTCEPSS rescore
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  6. 2026-07-11 08:26 UTCEPSS rescore
  7. 2026-07-09 21:45 UTCOSV refresh
  8. 2026-07-09 19:08 UTCEPSS rescore
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  36. 2026-06-21 07:31 UTCOSV refresh
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  49. 2026-06-12 23:11 UTCEPSS rescore
  50. 2026-06-11 13:59 UTCEPSS rescore
  51. 2026-06-10 22:17 UTCEPSS rescore
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  67. 2026-06-01 21:11 UTCOSV refresh
  68. 2026-06-01 13:51 UTCEPSS rescore
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Frequently asked(4)

What is CVE-2023-54203?
CVE-2023-54203 is a publicly disclosed vulnerability published on December 30, 2025. In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix slab-out-of-bounds in initsmb2rsp_hdr When smb1 mount fails, KASAN detect slab-out-of-bounds in initsmb2rsp_hdr like the following one. For smb1 negotiate(56bytes) , initsmb2rsp_hdr() for smb2 is called. The issue occurs…
When was CVE-2023-54203 disclosed?
CVE-2023-54203 was first published in the National Vulnerability Database on December 30, 2025, with the most recent update on April 15, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2023-54203 actively exploited?
CVE-2023-54203 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 92.8% of all scored CVEs.
How do I remediate CVE-2023-54203?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2023-54203, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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