CVE-2023-54203

CRITICALPre-NVD 9.19.1—
EchelonGraph scoreMEDIUM confidence

Score 9.1 from GitHub Security Advisory (severity: CRITICAL) published 2025-12-30. the CNA's CVSS baseline 9.1; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: cna:linux, epss, ghsa
9.1EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 1%CVSS: 9.1Exploit: 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
9.1
EG Score
9.1(medium)
EG Risk
46(Track)
EG Risk 46/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity91% × 45%
Exploitation0% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
1%
EPSS %ILE
44%
KEV
Not listed

Published

December 30, 2025

Last Modified

August 5, 2026

Advisory Details (4)

Auto-updated Sep 16, 2026
No patch confirmed yet.
generic

ksmbd: fix slab-out-of-bounds in init_smb2_rsp_hdr - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/dc8289f912387c3bcfbc5d2db29c8947fa207c11
generic

ksmbd: fix slab-out-of-bounds in init_smb2_rsp_hdr - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/99a51c673b1d2d0b5a972353401b77612d9cc713
generic

ksmbd: fix slab-out-of-bounds in init_smb2_rsp_hdr - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/a8334a0c535d0f0b4d64926c8fe0922ed98f7d43
generic

ksmbd: fix slab-out-of-bounds in init_smb2_rsp_hdr - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/921536046bd165efeb07beef5630aff35cd6a489

Vendor Advisories for CVE-2023-54203(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

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 / 28× 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 193 total refreshes for this CVE.

  1. 2026-09-20 20:14 UTCEPSS rescore
  2. 2026-09-20 20:14 UTCEPSS rescore
  3. 2026-09-19 21:50 UTCOSV refresh
  4. 2026-09-18 19:26 UTCEPSS rescore
  5. 2026-09-16 14:06 UTCEPSS rescore
  6. 2026-09-16 05:11 UTCEPSS rescore
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  8. 2026-09-15 03:08 UTCEPSS rescore
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  15. 2026-09-06 13:46 UTCEPSS rescore
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  20. 2026-09-01 13:52 UTCEPSS rescore
  21. 2026-09-01 04:36 UTCEPSS rescore
  22. 2026-09-01 01:04 UTCOSV refresh
  23. 2026-08-30 19:15 UTCEPSS rescore
  24. 2026-08-30 01:20 UTCEPSS rescore
  25. 2026-08-28 21:39 UTCEPSS rescore
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  1. 2026-08-27 14:23 UTCEPSS rescore
  2. 2026-08-26 14:44 UTCEPSS rescore
  3. 2026-08-25 13:47 UTCEPSS rescore
  4. 2026-08-23 00:17 UTCEPSS rescore
  5. 2026-08-23 00:17 UTCEPSS rescore
  6. 2026-08-21 23:47 UTCEPSS rescore
  7. 2026-08-20 22:53 UTCEPSS rescore
  8. 2026-08-19 17:02 UTCEPSS rescore
  9. 2026-08-18 13:46 UTCEPSS rescore
  10. 2026-08-16 14:54 UTCEPSS rescore
  11. 2026-08-16 02:12 UTCEPSS rescore
  12. 2026-08-15 01:28 UTCEPSS rescore
  13. 2026-08-15 01:08 UTCEG score recompute
  14. 2026-08-15 01:08 UTCGHSA enrichment
  15. 2026-08-13 21:58 UTCEPSS rescore
  16. 2026-08-12 13:49 UTCEPSS rescore
  17. 2026-08-11 13:40 UTCEPSS rescore
  18. 2026-08-10 23:58 UTCEPSS rescore
  19. 2026-08-09 22:23 UTCEG score recompute
  20. 2026-08-09 22:23 UTCGHSA enrichment
  21. 2026-08-09 13:44 UTCEPSS rescore
  22. 2026-08-08 16:35 UTCEPSS rescore
  23. 2026-08-08 08:51 UTCGHSA enrichment
  24. 2026-08-08 04:35 UTCEG score recompute
  25. 2026-08-08 04:35 UTCGHSA enrichment
  26. 2026-08-07 16:25 UTCEPSS rescore
  27. 2026-08-06 13:45 UTCEPSS rescore
  28. 2026-08-06 06:46 UTCEG score recompute
  29. 2026-08-06 06:46 UTCGHSA enrichment
  30. 2026-08-05 19:15 UTCEPSS rescore
  31. 2026-08-05 19:15 UTCEPSS rescore
  32. 2026-08-05 10:12 UTCEG score recompute
  33. 2026-08-05 10:12 UTCGHSA enrichment
  34. 2026-08-04 11:27 UTCEG score recompute
  35. 2026-08-04 11:27 UTCGHSA enrichment
  36. 2026-08-04 10:36 UTCEPSS rescore
  37. 2026-08-04 10:21 UTCEG score recompute▲ 9.10
  38. 2026-08-04 10:21 UTCGHSA enrichment
  39. 2026-08-04 10:19 UTCMITRE cvelistV5CVSS v3 → 9.1 · severity → CRITICAL
  40. 2026-08-03 10:34 UTCEPSS rescore
  41. 2026-08-02 02:25 UTCEPSS rescore
  42. 2026-08-02 02:25 UTCEPSS rescore
  43. 2026-08-01 04:14 UTCEPSS rescore
  44. 2026-07-30 16:26 UTCEPSS rescore
  45. 2026-07-30 01:29 UTCEPSS rescore
  46. 2026-07-28 15:34 UTCEPSS rescore
  47. 2026-07-28 15:34 UTCEPSS rescore
  48. 2026-07-27 03:09 UTCOSV refresh
  49. 2026-07-26 14:53 UTCEPSS rescore
  50. 2026-07-24 14:16 UTCEPSS rescore
  51. 2026-07-23 14:16 UTCEPSS rescore
  52. 2026-07-23 02:30 UTCEG score recompute
  53. 2026-07-22 23:16 UTCEG score recompute
  54. 2026-07-22 14:07 UTCEPSS rescore
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  56. 2026-07-21 15:23 UTCEPSS rescore
  57. 2026-07-20 17:06 UTCEPSS rescore
  58. 2026-07-19 14:30 UTCEPSS rescore
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  60. 2026-07-19 02:27 UTCEPSS rescore
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  62. 2026-07-18 10:03 UTCEPSS rescore
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  64. 2026-07-16 17:01 UTCEPSS rescore
  65. 2026-07-15 16:56 UTCEPSS rescore
  66. 2026-07-15 01:59 UTCEPSS rescore
  67. 2026-07-15 01:59 UTCEPSS rescore
  68. 2026-07-13 22:28 UTCEPSS rescore
  69. 2026-07-13 22:28 UTCEPSS rescore
  70. 2026-07-13 06:11 UTCEPSS rescore
  71. 2026-07-12 05:45 UTCEPSS rescore
  72. 2026-07-12 05:45 UTCEPSS rescore
  73. 2026-07-11 08:26 UTCEPSS rescore
  74. 2026-07-09 21:45 UTCOSV refresh
  75. 2026-07-09 19:08 UTCEPSS rescore

Related CVEs(same product)

Frequently asked(5)

What is CVE-2023-54203?
CVE-2023-54203 is a critical 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 August 5, 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 1% probability of exploitation in the next 30 days, which ranks it in the top 56.2% of all scored CVEs.
What is the CVSS score of CVE-2023-54203?
CVE-2023-54203 has a CVSS v4.0 base score of 9.1 (CNA self-assessment; NVD's own analysis pending).
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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